406 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 1991 VOL. 6 Conference Reports Fifth International Symposium on Resonance Ionization Spectroscopy and Its Applications (RIS-90) September 16th-21 st 1990 Varese Italy If scope challenge diversity of appli- cations and creativity are valid indi- cators Resonance Ionization Spec- troscopy (RIS) has come of age. These qualities and more were conspicuous during RIS-90. The inherent features of RIS in which tuned lasers are used to ionize atoms and molecules lead to analytical measurement systems which are far ahead of most conven- tional methods in both selectivity and sensitivity. It is the combination of these two qualities that is being em- ployed by scientists around the world to tackle a diversity of challenging problems which were reported at Var- ese by over 100 scientists representing 22 countries.At RIS-90 there was participation from USSR (Moscow and Leningrad) Finland Germany France Italy China Scotland Wales England Bel- gium United States Switzerland Canada and others. The involvement of the Institute of Spectroscopy (Tro- itsk) which George Bekov from the USSR Academy of Sciences initiated at RIS-88 grew considerably at the last meeting. Besides Bekov other mem- bers of the combined advisory and programme committees included J. E. Parks N. Omenetto E. Arimondo P. Benetti P. Camus G. Goldstein H. J. Kluge P. Knight Y . Y . Kuzyakov B. Lehmann A. L'Huillier T. Lucatorto C. M. Miller K. Niemax G. Rossi H. Rubinsztein-Dunlop J. C. Travis and T. J. Whitaker. The host organization for RIS-90 was the Commission of the European Communities Joint Research Centre Ispra Site Italy under the leadership of Professor N.Onienetto who served as Co-chairman of the symposium. Working closely with Professor Omen- etto was Co-chairman James E. Parks director of the Institute of Resonance Ionization Spectroscopy of the University of Tennessee (USA). The five-day meeting was packed with technical sessions in which 61 papers were delivered orally at 14 technical sessions and an additional 56 technical presentations were made at poster sessions. In addition 'A Short Course on Resonance Ionization Spec- troscopy' was conducted for an esti- mated 66 participants who were both beginners and seasoned experts of RIS. And there were special events perhaps the most significant of these was the judging and presentation of two awards which were inaugurated this year.One of these was given to the best work performed by a graduate student and another was given to the best work presented in a poster. As the quality of all of the technical papers (plenary and invited lectures oral and poster presentations) was notably high it is with some trepida- tion that any are singled out for discus- sion. The examples chosen represent the range and the flavour of the meet- ing with the trust that those not mentioned will not feel slighted. A strong theoretical component con- tinues to be a vital part of these Symposia on RIS. From the beginning of the RIS work at Oak Ridge National Laboratory Marvin G. Payne has made valuable contributions which were important in their own right and were critical for the innovation and conduct of new experimental demon- strations of the power of RIS.His contribution at RIS-90 dealt with co- operative effects which are sometimes pressure dependent during three-pho- ton excitation of atomic levels. There is good agreement between the theory and the experiments which shows that destructive interferences can greatly reduce the excitation probability in certain circumstances. Although these effects are rarely evident in RIS appli- cations it is a reminder that subtleties continue to emerge. About three years ago it was ob- served that there can be hyperfine structure effects in resonance ioniza- tion even with broad-band laser radia- tion. This problem attracted the atten- tion of another theorist P.Lambro- poulos of the University of Southern California and the University of Crete. With a laser that overlaps the hyper- fine manifolds the key parameters areJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY. SEPTEMBER 199 1 VOL. 6 407 Rabi frequency ionization rates hy- perfine splitting pulse duration and bandwidth. Detailed calculations were presented by Professor Lambropoulos and comparisons were made with ex- perimental data. Another subtlety in photoionization was discussed by Professor V. N. Os- trovsky of Leningrad State University who dealt with the problem of photo- detachment of electrons when negative ions are placed in an electric field. Oscillatory structure in the photode- tachment cross-section as a function of energy were explicable in terms of a model which involves the idea that when alternative paths connect arbi- trary points in space interferences are observed.This effect is reminiscent of Young's double slit experiment which shows wavelike interferences with either photons or electrons even when these are so low in intensity that as particles they would pass through the slit one at a time. Workers experimenting with vari- ous forms of ionization have always had to worry about collective pheno- mena or space charge effects which can make it very difficult to collect and measure the total ionization produced. During the past two meetings RIS-88 and RIS-90 Professor F. Giammanco University of Pisa Italy has been tackling these difficult problems for laser ionization in matter.He is now able to give quantitative descriptions that agree with laser ionization experi- ments and the theory is being ex- tended to the ejection of high energy electrons owing to the interaction of intense laser beams with surfaces. New Laser Sources and RIS Applications As all forms of laser spectroscopy including RIS depend on the avail- ability of suitable laser sources the programme committees for nearly all of the RIS symposia have invited speakers who could keep us up-to-date on leading edged developments on laser sources. This year R. Wallen- stein University Kaiserslautern Ger- many lectured on the generation of intense laser light from the extreme ultraviolet to the infrared. Professor Wallenstein discussed the use of Nd:YAG harmonics for optical par- ametric oscillation (OPO) in barium borate and lithium borate for the generation of coherent radiation which is continuously tunable in the range of 300-3000 nm.Frequency doubling and mixing in these all-solid- state lasers give wavelengths as short as 160 nm. Higher order frequency mixing with krypton and argon can even give wavelengths as short as 58 nm (20 eV). Another significant trend in solid- state lasers is the development and use of diode lasers as sources and as pumps for other lasers. K. Niemax who chaired the session on laser sources has made impressive contribu- tions in this area. J. P. Young of the Oak Ridge National Laboratory re- ported on the use of diode lasers for isoiopically selective RIS of lan- thanum. However not all of the novel RIS work is carried out using solid- state lasers.Novel work is also carried out on isotopic selectivity using CW- dye lasers for instance B. A. Bushaw Pacific Northwest Laboratory re- ported on the use of these methods for isotopes such as *loPo in context with the Radon problem. Copper-vapour laser technology has matured and has unique applications because of the high repetition rates as was reported by C. E. Webb Oxford Lasers. B. L. Fearey Los Alamos National Laboratory USA and his colleagues S. C. Johnson and C. M. Miller have been working on methods to make RIS methods more sensitive and reliable by using CW lasers. Their approach is to develop an external cavity which promises to increase the circulating laser power by about a factor of 100 and thereby to increase ionization efficiencies to the tens of per cent level.A new concept in the use of CW lasers for excitation and strong elec- tric fields for the final ionization step in RIS schemes was introduced by R. Hergenroder and K. Niemax Institut fur Spectrochemie und angewandte Spektroskopie Dortmund Germany. The novelty is in the spatial separation of the excitation and ionization re- gions. When these processes occur in the same region the strong electric fields cause Stark shifts and splitting of the high Rydberg states required for field ionization. This in turn causes a loss of selectivity in resolving one isotope from another. It was shown that lithium atoms when excited to n>30 would live long enough so that the atom could enter the ionization compartment before decay.Mechanisms Basic Experiments and RIS Data Service P. Agostini CEN Saclay France re- ported some intriguing new results on the multiphoton ionization of atoms in intense laser fields. When the photo- electron spectra are taken with ultra- short laser pulses at a fixed wave- length they show a complex structure which can be related to Stark-induced resonances. Analysis of these spectra reveal the energies of atomic levels directly under intense laser irradia- tion. The key point is the use of the ultrashort laser pulses as the features of the energy levels wash out with the use of longer laser pulses. Basic experiments on excitation mechanisms in laser enhanced ioniza- tion (LEI) in flames were reported by Ove Axner Chalmers University of Technology Goteborg Sweden.Line shapes for two-step ionization and other experimental features could not be treated with a rate equation theory yet the density-matrix formulation does give satisfactory agreement. In other work on LEI N. Omenetto and his colleagues at the Environment In- stitute of the JRC Ispra have been able to record directly the Raman spectra of molecules while using atomic con- stituents of flames as novel photon detectors. The basic principles of the ionization of atoms in hot cavities have been investigated by V. I. Mishin at the Institute of Spectroscopy in Troitsk USSR. Particular attention was given to ion extraction permitting efficient detection of the lanthanide atoms in such cavities. The National Institute of Standards and Technology (NIST) of the United States has established a data service on RIS. Building on a long tradition (as the National Bureau of Standards) in Atomic Physics Data the NIST pro- gramme offers RIS data sheets on individual elements. Judging from the presentation by E.B. Saloman and the response generated from the devel- opers and users of RIS it appears that the new service is destined to have a bright future. RIS Applications to the Study of Rare Atoms One of the highlights of RIS-90 was a report on the applications to the study of rare atoms. As Professor H. J. Kluge Institut fur Physik Universitat Mainz Germany stated in his plenary paper much of our knowledge on the atomic nucleus has come from optical studies. Quantities such as nuclear spin magnetic dipole moment and spectroscopic quadrupole moment have been determined from optical spectroscopy as the hyperfine struc- ture is revealing these and other nu- clear parameters.On-line mass separa- tors equipped with techniques of laser spectroscopy for the determination of hyperfine structure in long chains of short-lived isotopes has made it pos- sible to catalogue the ground-state properties of some 30 elements involv- ing about 500 nuclear ground and isomeric states. The group of Professor Letokhov at Troitsk has collaborated with Profes- sor Kluge and his colleagues at Mainz in pioneering the use of RIS in many of these studies. Closely related work is being carried out by Professor A. E.408 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 199 1 VOL.6 Barzakh Leningrad Nuclear Physics Institute USSR. A great deal of RIS work is also carried out at ISOLDE/ CERN ISOCELE/Orsay and Gatchina/ Leningrad. Professor J. E. Crawford and his colleagues at McGill Univer- sity are collaborating with groups at Orsay to study the nuclear properties of gold and platinum isotopes. Detec- tion of very rare isotopes in which RIS is applied to collinear techniques was reported by Yu. A. Kudryavstsev at Troitsk. This powerful technique for obtaining high isotopic resolution is based on the production of large kine- matic isotope shifts in accelerated atoms moving collinearly with the laser beam. For atoms such as 3He having high ionization potentials metastable neutrals are first produced by charge exchange between the atomic ion and a suitable metal vapour.A tradition in the RIS symposium is to invite speakers to represent non- RIS methods for difficult analytical problems. This year Martin Suter Paul Scherrer Institut Zurich Switzer- land gave a plenary lecture on an accelerator mass spectrometer for rare isotopes such as l0Be and 14C. This method uses very mature technology as compared with RIS and sets a high standard for the detection of rare species such as 14C. Applications of RIS to Materials Science N. Thonnard Atom Sciences Oak Ridge TN USA outlined the devel- opment of the analytical capabilities for the analysis of surfaces and the bulk characterization of materials by depth profiling using the sputter- initiated RIS technique known as SIRIS. This technique pioneered by J.E Parks and others at Atom Sciences and by N. Winograd at Pennsylvania State University has some features in common with the well-known SIMS method. However in SIRIS the secon- dary ions generated by the impact of the ion beams on the surface are not the signal of interest; it is rather the signal generated by RIS on the sput- tered neutral atoms. The central idea in this more complex instrument is that the analysis of impurities in ma- terials should be more sensitive and relatively free of matrix effects com- pared with SIMS. That these features can be advantageous was dramatically demonstrated by S. W. Downey AT&T Bell Laboratories Murray Hill NJ USA. Dr. Downey showed results for the depth profiling of Be atoms at the interfaces of GaAs-A1As and InGaAs-InAIAs structures.The clean features of these interfaces are not seen nearly so well with the SIMS technique where large matrix effects obscure the boundaries. Equally impressive results using the SIRIS technique were re- ported by George Havrilla BP Re- search Cleveland OH USA on the analysis of silver-gold structures where again drastic improvements in the definition of boundaries was ob- served and was attributed to reduced matrix effects. Dr. Matthew H. Ervin with the Winograd group reported some fasci- nating studies of polycyclic aromatic compounds and several molecules of biological interest which were deposi- ted on the upper layer of solids. These molecules could be photo-desorbed in a process described as ‘gentle’ such that the released molecules were neu- tral and intact.Further when the RIS process was used to ionize these mainly the parent positive ion was found. These strikingly clean results have led to an analytical system with sensitivity at the ferntomole level. Environmental and Trace Analysis Because of pressing applications new developments in trace analysis espe- cially for environmental applications is taking place at a rapid rate. The well-known approach at the Institute of Spectroscopy at Troitsk in which a graphite furnace is used as the atom- izer was reviewed by George Bekov. The free atoms are then stepwise ex- cited in resonance processes to a Rydberg state where field ionization occurs. High sensitivity efficient atomization and other features were described that show laser analytical photoionization spectrometry (LAPIS) is capable of handling a wide variety of environmental problems.R. Zilliacus Technical Research Centre of Finland studied the problem of precision using a system similar to the LAPIS system of Bekov. Of special attention is the matrix effect which is smaller with the graphite furnace than many other types of ionizers. The group in Finland (Zilliacus Likonen and Auterinen) is making progress using various tricks of chemical modification to achieve precisions of a few per cent. For several years the KIS group at Tsin- ghua University has been developing an analytical system for the direct analysis of gold and other precious metals in minerals. At RIS-90 the authors (Hui Niu Cheng Xu and Zhao under the direction of D. Y . Chen) reported on a spectacular sensi- tivity for the analysis of gold in miner- als.They find detection limits of 10 ppt with backgrounds of the same order. The Tsinghua group uses a thermal atomizer followed by three resonance steps the last being an auto- ionization level. Not all trace analysis belongs to the environmental areas. H. Lauranto Helsinki University of Technology Finland discussed the use of RIS to measure the neutron dose in pressure vessels of nuclear reactors. The idea is to measure the concentration of the nuclear isomeric state compared with the nuclear ground state of 93Nb which increases in direct proportion to the neutron flux that can embrittle the vessel. A RIS scheme for distinguish- ing the two nuclear states based on hyperfine splitting of certain optical levels was presented.F. Ames Universitat Mainz Ger- many along with his colleagues at Mainz and the Bhabba Atomic Re- search Centre Bombay India devel- oped a RIMS system for the measure- ment of the 8B solar neutrino flux. The special feature of this experiment pur- sued also at Los Alamos National Laboratory is that it would measure the neutrino flux integrated over the past several million years and would thus test the constancy of the sun. The method requires the analysis of about 1 x I O8 atoms of 9 7 T ~ or 9 8 T ~ along with about 1 x 10’ atoms of 99Tc and about 1 x lo1* atoms of Mo. An ingenious furnace was developed such that when operated at 2300 K the atoms to be detected would be confined inside a cavity where they cross the RIS beam many times.Ions extracted from the cavity were mass analysed with a high resolution mass spectrometer. A novel method for the direct analy- sis of semiconducting materials using LEI was developed and presented by N. V. Chekalin V. I. Verdansky Insti- tute of Geochemistry and Analytical Chemistry Moscow USSR. This so- called ‘rod-flame’ method uses a confi- guration in which the sample can be directly evaporated from a graphite rod into a flame where atomization of the sample and where the LEI process occurs on the thermally dissociated atoms. The rod-flame method is 3-4 orders of magnitude more sensitive than conventional atomic absorption in flames. R. D. Willis Atom Sciences re- ported on the use of RIS to measure 81Kr in lunar rocks and meteorites. A method for measuring cosmic-ray ex- posure ages of such materials has been pioneered by Professor 0.Eugster University of Bern Switzerland in which a mass spectrometer is used to measure 81Kr along with at least one cosmogenic stable isotope of Kr and from the ratio the exposure age is calculated. A measurement was made at Bern by Eugster Th. Michel and B. E. Lehmann using a special mass spec- trometer and a measurement was made in Oak Ridge using RIS in a TOF mass spectrometer. The agree- ment on the exposure age (more thanJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 1991 VOL. 6 409 The Russian delegation of scientists clearly en.jo-ving themselves at the Conference Dinner on Thursday evening 20 million years) was excellent even when the sample measured at Atom Sciences was about 50 times smaller than that of the Bern measurement.The pay-off in using RIS is that much smaller sample sizes can be used perhaps by more than two orders of magnitude. Biological and Medical Applications Progress on the application of RIS and other laser methods to biological and medical problems continues. In a ple- nary lecture Professor Sune Svanberg Lund Institute of Technology Lund Sweden reviewed the use of laser spectroscopy such as coherent and anti-Stokes Raman scattering laser induced fluorescence and others in the mapping and quantification of atmos- pheric pollution. In medicine lasers are used to detect cancer in addition to photochemically treating them. Fol- lowing the injection of tumour-seeking agents lasers can be used to induce fluorescence in the diseased areas.By using time-gated optical illumination of the tissue with picosecond laser pulses blurring as a result of scattering can be reduced giving new possibili- ties for mammography with non-ioniz- ing radiation. I. K. Perera and colleagues at Uppsala University Uppsala Sweden reported progress on the use of UV lasers to desorb and ionize large mole- cules of biological interest. These ions are then analysed with a TOF mass spectrometer up to a mass range of 200000 u to study peptides polypep- tides and proteins. The RIMS technique is making im- portant contributions to diabetes hae- matology toxicology neonatology and neurology by analysis of trace elements such as chromium iron copper nickel and molybdenum. These results were reported by L.J. Moore Eastern Ana- lytical College Park MD and repre- sent a collaboration with Atom Sci- ences in Oak Ridge. Another significant contribution to the biological sciences is being made by H. F. Arlinghaus and his colleagues at Atom Sciences in their teaming with K. B. Jacobson of Oak Ridge National Laboratory to develop a much more rapid sequencing technique for the human genome. The approach is to label the four nucleotide bases with stable isotopes and to detect these isotopes using RIS in the SIRIS sys- tem. Encouraging results show that by speeding up the analysis with the high pulse rates of a Cu-vapour laser it should be possible to process 10 mil- lion base pairs per day and thus an entire genome could be sequenced in one year. Molecular Studies Many of us would not have predicted that laser ionization of large mole- cules would ever produce the beau- tiful results that were presented at Varese.For instance J. Grotemeyer Garching Germany uses a wide range of laser wavelengths to desorb and ionize molecules such as amino acids proteins nucleotides and pep- tides. Supersonic jets were used to keep the neutral molecules intact. The RIMS studies of naphthalene toluene and aniline were reported by A. Marshall University of Glasgow UK. Some very interesting results were discussed by U. Boesl Universi- tat Munchen Garching Germany. By Jim Parks congratulates Mohamed El- Maazawi winner of the Poster Award. The work was carried out at the Pennsylvania State University under the direction of Professor N.Winograd Roland Hergenroder student to Professor Niemax receives the congratulations of Jim Parks (lefl) and Sam Hurst (centre) as the recipient of the Graduate Student Award. The ceremony took place during the Social Dinner using benzene as an example it was shown that the multiphoton ioniza- tion of large molecules can occur in a sequence called ‘ladder-switching’ in which ion dissociation can be so fast that further absorption takes place in a fragment which further dissociates and so on to propagate the sequence.410 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 1991 VOL. 6 Awards Two awards were made at RIS-90. One of these was for the best work per- formed and presented at the sympo- sium by a graduate student. Another award was for the best poster and was open to all participants.The Award for best poster presentation was made to Mohamed El-Maazawi who happened to also be a graduate student. Along with the honour Dr. El-Maazawi re- ceived a cash prize of US$200.00 provideq by an anonymous donor and copies of the books by Professor Leto- khov on ‘Laser Ionization Spectro- scopy’ and Hurst and Payne on ‘Reso- nance Ionization Spectroscopy’. For the Graduate Student Award there were 10 entries and all of them represented excellent work. The judg- ing committee was very impressed and took the evaluation process very seri- ously. At the social dinner the top three places were recognized. In third place was Q. Hui a student of Professor D. Y. Chen at Tsinghua University in Beijing People’s Repub- lic of China.The title of this work was ‘Ultrasensitive Analysis of Gold in Mineral Samples Using Resonance Excitation and Auto-ionization Mass Spectrometry’. In second place was F. Ames a student of H. J. Kluge Universitat Mainz with an entry entitled ‘RIS of Technetium in a Laser Ion Source for a So1a.r-Neutrino Exper- iment’. However the Award went to Roland Hergenroder a student of K. Niemax Institut fur Spektrochemie und angewandte Spektroskopie. The Award was made for the development of the ‘Continuous Wave Field Ioniza- tion Laser Spectrometer’. For this out- st anding contribution Dr . Hergenro- der received a plaque and a cash prize of US$lOOO provided by the Institute of Resonance Ionization Spectro- scopy Physics Department Univer- sity of Tennessee. Thanks are due to the many spon- sors for their financial and moral support.These were CNR Comitato Nazionale Scienze Chimiche; ENEA; Istituto Nazionale Fisica Nucleare; Environment Institute JRC Ispra; dB Electronics; Elicam; ISA Italia; Laser Optronic; Microcontrole; VG Instru- ments; Atom Sciences; US Depart- ment of Energy Office of Health and Environmental Research; Battelle Pacific Northwest L,aboratories Mole- cular Sciences Research Center; EG & G Energy Measurements; Los Alamos National Laboratory; Martin Marietta Energy Systems; Perkin-Elmer Physi- cal Electronics Division; National Institute of Standards and Techno- logy; and the Institute of Resonance Ionization Spectroscopy and the Sci- ence Alliance of The University of Tennessee. The continued interest of the US Department of Energy and especially the strong interest and leadership provided by Gerald Goldstein of the Office of Health and Environmental Research is much ap- preciated.The complete proceedings of RIS-90 are available from IOP Publishing Bristol UK. The RIS-92 is planned for May 24-29 1992 Santa Fe New Mexico. Those interested in further informa- tion should contact the Institute of RIS or C. M. Miller at Los Alamos National Laboratory. One of the main goals is to continue the strong partici- pation of graduate students which started at Varese through the efforts of Professor Omenetto. The Graduate Student Award and the Poster Award will be a continuing part of the sym- posia. Tutti si sono divertiti moltissimo! G. Samuel Hurst Institute of Resonance Ionization Spectroscopy 10521 Research Drive Suite 300 Knoxville TN 37932 USA XXVll CSI Pre-Symposium on Graphite Atomizer Techniques in Analytical Spectroscopy June 6th-8th 1991 Hotel Ullensvang Lofthus Norway I have to admit that after nearly two months of non-stop travel and having only two days before the start of the pre-Symposium flown back from Ja- pan the thought of travelling to Nor- way for the CSI meeting was not one I viewed with any enthusiasm. The all day journey culminating in a four hour bus transfer from Bergen to Lofthus on narrow twisting roads along the Nor- wegian Fjords (what no parrots?) did not auger well.However both myself and the other participants (approxi- mately 120) were to be rewarded with what in my opinion was one of the best electrothermal atomization meet- ings that I have attended in the last 4-5 years.The organizers Bernhard Welz and Wolfgang Frech are to be roundly congratulated for such a wide ranging and informative meeting. They also introduced several new sym- posium management techniques that I feel sure will become accepted practise in the future. The first requirement is to organize the meeting in a good hotel in an area Bernhard U’ek om7 of the con-krence organizers in a more relaxed monieiit of outstanding natural beauty which has a high propensity for torrential rainfall in the summer. This ensures an almost 100°/o attendance at all of the lectures. Secondly ensure that the final speaker of each session is the Chair- man of that session. This concentrates the mind of the Chairman on making sure that everyone keeps to time as both myself and Chris Mullins dis- covered.Thirdly organize the meeting in a country where alcohol is prohibi- tively expensive this guarantees that everyone will be on time for the first lecture of the day. Finally ensure that the sun comes out in time for the excursion tour. Without a shadow of a doubt Drs. Welz and Frech have set the organizational standards against which all other future meetings will be measured. The meeting was opened on the Thursday morning by Sir Alan Walsh who apologized for never having used an atomic absorption instrument with a graphite electrothermal atomizer but that he had realized the feasibility of the technique for absolute analysis early on which had subsequently been demonstrated and expanded on by Professor L’vov.The first half of the morning session was comprised of a series of lectures examining the structure and nature of reactions on the surface of graphite. Professor Yang (State University ofJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 1991 VOL. 6 41 1 New York at Buffalo) gave a fascinat- ing lecture entitled ‘Electron Micros- copy Study of Gas-Carbon Reactions’ which considered the probable nature of reactions between metal atoms and the edge carbons of the graphite crystal plane at elevated temperatures in the presence of water carbon dioxide and oxygen. Some stunning electron mi- crographs were shown of metal par- ticles ‘eating’ their way in a regular fashion along the edge carbons which might be a result of the carbon dissolv- ing into the metal droplet which ‘pulls’ the metal particle along.This was followed by Professor Ortner (Techni- cal University of Darmstadt) with his lecture ‘Materials in ETAAS-a struc- tural and morphological review’ which examined graphite surfaces on a slightly larger scale but illustrated how important the microstructure of the graphite surface is in terms of its lifetime. Following these two lectures what turned out to be the ‘hot topic’ of the meeting was introduced by Professor Boris L‘vov (Leningrad State Techni- cal University) with his lecture ‘Gase- ous Carbide Concept in GFAAS State of the Art’. A review of the develop- ment of the theory and the author’s experimental evidence contrasted with a differing interpretation of recent results published by Holcombe et al.This prompted a heated debate which was continued in a discussion later that evening. The next two lectures discussed the opposing theories on the subject of reduction by gaseous car- bides. Dr. Dave Styris (Pacific North- west Laboratory) with ‘Atomization Mechanisms from Real-Time Gas Phase Mass Spectra Clues from Car- bides and Oxides’ discussed the differ- ences between vacuum and atmo- spheric vaporization. If both of these are performed then one can separate out the gas phase from the surface effects. From his studies he concluded that the atomization mechanisms of In Ga and A1 were a result of thermal decomposition. Following on from this came Professor Jim Holcombe (University of Texas) with ‘Alumi- nium Spikes and Mechanisms for Alu- minium Vaporization’.This intensi- fied the debate as Jim Holcombe pre- sented his and his co-workers interpre- tation of the spikes sometimes formed by the atomization of large amounts of A1 in a graphite electrothermal atom- izer. However there were no dissent- ing voices when Jim Holcombe stated that ‘spikes are fascinating’ he went on to say that the generation of spikes is frustrating and that in his opinion the direct observation of spikes does not support the gaseous carbide theory and that there are so many dependent variables that everything is very con- fusing. A conclusion that nobody in the audience at Lofthus would disagree with. He presented a range of results from mass spectra studies to those from Monte Carlo modelling and ended up by presenting more ques- tions than answers.However the lec- ture stimulated a considerable discus- sion as only now is the gaseous carbide theory being rigorously examined by a variety of groups around the world. The results of all of these investiga- tions can only be to improve our understanding of what is happening within a graphite electrothermal atom- izer for which Professor L‘vov and his theory of gaseous carbide reduction has been the catalyst. To conclude the first mornings session Dr. Gilmutdi- nov (University of Kazan USSR) pre- sented his teams work on ‘Dynamics of Atomic and Molecular Layers in Graphite Furnace AAS’. The distribu- tion and generation of atomic and Time for a break during the poster session Boris L ’vov Dave Styris Debbie Bradshaw and Jim Harnly molecular layers during the atomiza- tion stage in a graphite atomizer were examined using shadow spectral film- ing.Some very interesting results were presented showing atomization from both the wall and the platform for a variety of elements and showed strong non-uniform distributions across the atomizer which depended upon the element. Both sides in the discussions used the data to support their own particular interpretation. By now it was time for lunch and the partici- pants walked stunned into the hotel restaurant. This had to be one of the most stimulating mornings collection of papers I had ever experienced and the general consensus gained during lunchtime discussions confirmed these feelings. The afternoon session continued with more mechanistic considerations with Professor Cor Rademeyer (University of Pretoria) considering the atomization mechanism of silicon in the presence of oxygen and carbon monoxide.This was nicely followed with Dr. Wend1 (University of Karls- ruhe) considering the role of oxygen in the determination of oxide forming elements such as T1 Bi Cd and Pb. On a slightly different tack Dr. Huie (State University of New York at Binghamton) presented results exam- ining the gas dynamics in a graphite atomizer using the absorption from Na and laser sources. The laminar and turbulent gas flows in a transparent cylindrical glass tube with the same dimensions as a graphite atomizer were assessed although as a number of questions pointed out his experi- ments were performed at room tem- perature which is somewhat different to the real situation however the information was valuable.Dr. Douglas Baxter (University of Umeii) made a stunning entry from the back of the lecture theatre in complete traditional Scottish dress and presented his results on assessing the spatial distribution and partial pressures of Cz and CN molecules in an integrated contact atomizer. Douglas was to be congratu- lated on starting his lecture with a geography lesson showing a sketch map of where we were in Norway and where Umeii is in relation to Lofthus. I was indebted to this overhead as up until that point I had no idea of where I was in relation to the rest of Norway although the worst question of the meeting had to be ‘Do all Scotsmen wear dresses?’ Dr. Yasuda (Hitachi) then presented some work on measur- ing gas temperatures in a graphite atomizer using the ‘two-line’ method which is now accepted as only giving an approximate measure of the aver- age temperature in the atomizer. The afternoon session was concluded by Dr.Marowsky (Max-Plank Institute for Biophysical Chemistry) who dis- cussed the information that can be extracted from gas phase systems (such as temperature measurements) using non-linear optics and the fact that degenerate four-wave mixing provides much better detection sensitivity than that of non-resonant CARS. As a very non-physical chemist I was prepared to take his word however there is no denying Dr. Marowsky’s enthusiasm for his subject and during a subsequent lunchtime discussion he convinced me that he could solve all our problems with laser beams.But as always it is a question of time and money. The evening discussion with the provocative title of ‘Modelling of Graphite Furnace Processes What Do We Know?’ rapidly moved on from the suggested topic of modelling to that of the reduction by gaseous car- bides. In the blue corner we had Professor Boris L‘vov and in the red corner Professor Jim Holcombe and412 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 1991 VOL. 6 we the assembled throng waited with baited breath for the heavyweights to slug it out! It rapidly became clear that there are no firm protocols or ideas on how to investigate atomization mecha- nisms or interference mechanisms and that without further evidence we are left with interpretation of experimental data which can often be conflicting depending upon the starting point or opinions of the individual scientist.The discussion was ably led by Wolf- gang Frech who bravely kept the whole thing under control and the evening was notable for the two occasions when Jim Holcombe said that he agreed with Boris L'vov on particular points. 'Is this possible' asked the assembled masses? (An abridged version of the discussion will appear in the confer- ence issue of JAAS next March.) Following the main discussion a small group of well-known scientists were seen later to be huddled in a corner until the small hours of the morning discussing believe it or not gaseous reduction by carbides. Another not so well-known group re- tired to the back of the lecture theatre and with the aid of some not inconsi- derable amounts of imported duty free liquor discussed deep and meaningful questions such as the probability of whether it would continue to rain on the following day and whether any programme session could ever hope to finish on time? Only experience would tell as an extremely nervous future Chairman wound his weary way to bed! The Friday morning session was devoted to combined techniques and featured presentations from Dr.Welz (Bodenseewerk Perkin-Elmer) and Professor Fang (Academica Sinica Shenyang China) on flow-injection on-line preconcentration procedures coupled with a graphite electrothermal atomizer. This is a technique that seems to be increasing in popularity and offers a relatively contamination- free method of improving detection limits and extending the range of ETAAS analysis to lower levels.These two lectures were complemented by those of Walter Slavin (Perkin-Elmer) and Professor Ni (Academica Sinica Beijing China) who considered the trapping of gaseous hydrides and alkyl- selenides within a graphite electrother- mal atomizer. Professor Ni described the coupling of GC with ETAAS for the determination of alkylselenides. The alkylselenides were separated by gas chromatography and the eluted species led directly into a palladium coated graphite tube and trapped at a temperature of 500-600 "C. There appeared to be sufficient time for the operation of the furnace programme during the time interval between each elution peak. Dr. de Loos-Vollebregt (Technical University Delft) con- tinued with this theme and discussed the speciation of organo-metal com- pounds with HPLC-thermospray coupled with a graphite electrothermal atomizer. Professor Chakrabarti (Car- leton University Canada) then consi- dered the use of electrothermal vapori- zation coupled with ICP-MS to inves- tigate the chloride interferences in graphite electrothermal atomizer AAS on the determination of Mn in 1% HC1.The fact that wall atomization was used for the investigation when this interference can be overcome by the use of a platform and/or chemical modification was the subject of some pertinent questioning. To conclude the mornings session the Chairman (the Presentation to Bruno Hiitsch The poster session author of this report) described the development and application of an instrument using the longitudinal Zee- man-effect for background correction combined with a transverse heated graphite electrothermal atomizer.The afternoon session was devoted to viewing the posters of which 50 were presented and sub-divided into the following subject areas separation preconcentration and sequestration; instrumental developments; reaction and atomization mechanisms and modelling; solid samples and slurries; interferences and modifiers; and last but not least applications. An ex- tremely wide range of posters were presented and most of the participants spent the entire afternoon in detailed discussion with the various authors although the steady and persistent rainfall might have had something to do with this.Both before and after the evening meal group discussion sessions were organized concerning the posters. The evening poster discussions were pre- ceeded by a presentation of a gold graphite tube with a diamond injec- tion hole in the form of a tie pin and an accompanying certificate signed by the participants. They were awarded to Bruno Hutsch of Ringsdorff GmbH as a small token of the appreciation for all his help and assistance over the years with the fabrication of all of the myriad different graphite tube and platform designs that many of us have required for our research and often obtained at no expense. Following the presentation Dr. Gilmutdinov showed actual film of some of his shadow spectral results. These results certainly stimulated some thoughts as to what we were really observing in a graphite atomizer.The range of subjects and areas considered by the posters was large and only a flavour can be given here. Clearly the subject of speciation is one that is starting to receive serious attention not only from the point of analyticalJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 199 1 VOL. 6 413 methodology but from the more se- rious aspect of what are we really measuring? How can we be sure that we are not disturbing the equilibrium of the various species? All present agreed that quality control samples are needed with certified values for differ- ent species. The hardy perennial of standardization in slurry and solid sampling was once again discussed. With multi-element techniques inter- nal standardization can be used but one has to confirm that it works.Some discussion centred on the limitations of the Zeeman-effect for background correction especially when small mole- cules such as PO are present. However it was concluded that while there are certain situations where there are problems with Zeeman-effect back- ground correction these are very rare and hence it is still the best method. During the evening discussion the topic of nomenclature reared its mal- ign head courtesy of Bernhard Welz and considerable time was devoted to the discussion of what symbol we should use for integrated absorbance? The term As is false as integrated absorbance is a dimensionless unit but with this terminology the units should be seconds. The term A has been proposed for peak absorbance and discussion centred on the use of A,nt for integrated absorption.Just to round off the evening we were all told that we should stop using the term furnace and that IUPAC recommends the term atomizer. Therefore in the preparation of this report I have tried to use the term atomizer throughout. Saturday morning and the start of the final session was greeted with sunshine much to our amazement Even though Dr. Yngvar Thomassen had promised us all fine weather for the Saturday afternoon excursion most of us had considered that this was wishful thinking on his part or that he had a direct line to God. It would appear that the latter was correct. The final session was devoted to the exami- nation of some of the new techniques being developed involving the use of graphite atomizers as a source of either atoms or ions for emission measure- ments.Professor Mike Blades (Univer- sity of British Columbia) started with a discussion of the ‘Recent Develop- ments in Furnace Atomization Plasma Excitation Spectroscopy’. The FAPES source has the potential for carrying out simultaneous multi-element analy- sis and Mike described his system which uses an isothermal side-heated graphite atomizer with a central graph- ite rod powered by a radiofrequency generator enabling the formation of plasmas at atmospheric pressure. The system is flexible and allows a compar- ison of both atomic emission and absorption signals. Dr. Ralph Sturgeon (National Research Council of Canada) discussed the use of the FAPES source to examine molecular species and to assess the effects of modifiers on these species in an effort to provide more information about what is happening during atomization in a graphite atomizer.The multi- element theme was expanded by Dr. Jim Harnly (United States Depart- ment of Agriculture) who presented work on the various techniques used to improve the performance of contin- uum source AAS. These included an improved optical configuration pho- todiode array detection in conjunction with a larger spectral bandpass and pulsing of the xenon arc continuum source. Dr. Heinz Falk (Spectro Ana- lytical Instruments) discussed the ‘Ul- trasensitive Detection of Atoms and Ions using Graphite Furnaces’ and indulged in a little bit of crystal ball gazing to consider the possibilities of single atom detection using laser exci- tation and trapping within graphite atomizers.Although feasible in princi- ple I noted the wry irony in Dr. Falk’s voice when he concluded that the level of experimental expenditure to de- monstrate this would be high! The potential of ‘Laser Induced Flu- orescence (LIF) Spectrometry as an Analytical and Diagnostic Tool in Graphite Atomizers’ was presented by Dr. Sten Sjostrom (Chalmers Univer- sity of Technology). This technique has detection limits in the femtogram range high selectivity and a large dynamic range and in the opinion of Dr. Sjostrom is justified for demand- ing ultratrace analyses. Although a major limitation appears to be the availability of cheaper lasers covering a wider wavelength range. The penulti- mate lecture was presented by Dr.Ken Jackson (State University of New York) on the ‘Physical and Chemical Mechanisms of Modifiers in Slurry ETAAS’ however he decided to re- name his lecture ‘Only God Knows How Pd Works as a Modifier’ in response to comments made the previ- ous day by Professor Chakrabarti con- cerning what goes on in an atomizer (maybe he should talk to Yngvar?). Palladium is widely accepted as a modifier however its mechanism of action in slurry analysis has not been widely investigated and results indi- cating a more physical than chemical effect were shown. The concluding lecture was from Dr. Chris Mullins (Varian) on the determination of man- ganese in urine using platform atomi- zation and preconcentration via mul- tiple injections. After such an arduous two and a half days of lectures a half day excursion was organized to enable us to relax unwind and admire the spectacular Norwegian countryside.I make no apologies for these gushing sentences as they are lifted directly from the symposium programme. I am certain that if Drs. Welz and Frech grow tired of science then they are assured of a successful future as advertising copy writers. (The money cannot be any worse!) Following a pleasant after lunch stroll in glorious sunshine round the small village of Lofthus (some brave souls even ventured by rowing boat onto the fiord) and entertainment by the local marching bands we boarded the buses for our visit to the Hardangervidda the largest mountain plateau in Northern Europe. Along the way we stopped at the Sima electricity generating plant which is built 700 m inside the mountain side at Eidfjord where we were shown an interesting film about the construction of the power plant.Heavy snowfall takes on a whole new meaning when you see pictures of ‘dwarf-like’ snow blowers attempting to cut through 10 m high snow drifts! From here we climbed slowly up to the Voringsfoss waterfall. This steep twisting road had me wish- ing that I had brought my motorcycle to Norway. The Voringsfoss waterfall has a free fall of over 183 m and is certainly spectacular. What was also entertaining was to see the look of absolute horror on the face of our tour guide as over 120 people scrambled to the very edge of the ravine to get good photographs clambered all over the wet slippery rocks and generally took more risks than he would have liked.I am certain that he had visions of seeing more than one person go Enjoying Saturday afternoon ’s excursion Barbara Dittrich (Leipzig Germany) and Marcella Sucmanowa (Brno Czecho- slovakia)414 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 199 1 VOL. 6 through a ‘birdman-crater (or splash!)- total’ sequence. Fortunately we all returned safely to the buses although I had tried to convince Ken Jackson that throwing himself into the ravine would have made a spectacular picture for this JAAS report and would assure him of a legendary status within our community. From here we continued up to the plateau and marvelled at the amount of snow still on the ground before stopping at the Halne Mountain Lodge where we were served a superb buffet of typical Norwegian hot and cold dishes.Those of us with some experience in these matters made straight for the reindeer goulash the enormous smoked salmon and the Norwegian sweet porridge with cinna- mon which is eaten as a dessert. This delightful though not terribly inter- esting looking dish became a firm favourite with a small select group of aficionados. Following our return journey the final evening ended up with a considerable number of the participants taking over the hotel foyer and indulging in a late night inter- national joke-telling competition with notable contributions from Jim Harnly for ‘The Gorilla Story’ Nancy Miller-Ihli for ‘The Wendy tale’ and a seemingly never ending stream of jokes from Mike Blades.Social highlights of the meeting were the phenomenal drinking exploits of a couple of English scientists who shall remain nameless although they wish to apologize publicly to Zvone Gro- benski for drinking his bottle of slivo- vitz. Dr. Grobenski organized the early morning jogging sessions which sadly I missed due to Phil Riby keep- ing me up past my bed-time! Most people also missed the disgusting early morning spectacle of a relatively young English scientist being abso- lutely thrashed at squash by a well- known Texan Professor of Chemistry. The final seven hour coach journey back to Bergen for the CSI meeting was enlivened for the people at the back of our bus as one participant and a well-known journal editor indulged in what is euphemistically known to the English as ‘jovial banter’ but to those in the near vicinity who are unaware of this custom may have appeared to be some form of ritualistic verbal abuse normally carried out be- tween sworn enemies. Throughout the three days of this symposium stimulating ideas were presented new directions examined and I went away with my intellectual batteries recharged my liver crying out for a rest and total panic taking hold every time I thought about how I was going to write about all these lectures for next years ASU review.In conclusion I would once again like to thank the organizers for an excellent meeting. From both a scientific and social point of view we all had a very enjoyable time. I look forward to seeing everyone at the next ETAAS Post-CSI symposium somewhere in Northern England in 1993.Who- ever convinced me to organize this has no idea of how hard it is going to be to follow such an impressive act.. . Ian L. Shuttler Bodenseewerk Perkin-Elmer GrnbH Uberlingen Germany XXVll Colloquium Spectroscopicurn Grieg Hall Bergen Norway Internationale Continuing in the tradition of the CSI meetings the XXVII in Bergen Nor- way afforded an opportunity for ana- lytical spectroscopists from around the world both to learn of the latest devel- opments and to discuss them with their peers. The CSI is truly the most international of analytical spectros- copy meetings and on this occasion 27 countries were represented. What bet- ter place to become acquainted with the person whose name you know so well from their published work.And then there are old friends ever willing to discuss their latest ideas and to share in the pleasures of the social gatherings. The main conference venue was the Grieg Hall in Bergen where the plenary lectures and poster sessions were given and which housed the instrument exhi- bition. The contributed papers were organized into six parallel sessions which were presented in the lecture theatres of the University a few min- utes walk away from the Grieg Hall. The scientific programme covered all of the major branches of analytical spectroscopy including optical X-ray mass NMR and electron spectrome- try. The two opening plenaries dealt with sources somewhat larger than those normally encountered in the analytical laboratory namely stars and inter-stellar clouds.Analytical spec- troscopists familiar ,with using wave- length or mass tables to identify the presence of particular species will feel fortunate in not having to interpret spectra that have been Doppler shifted to unfamiliar wavelengths. Here the wavelength separations and intensity ratios become the key identifiers and it is perhaps not surprising that the use of multi-pixel detectors pioneered in astronomy are now beginning to have an impact in analytical spectroscopy. An unusual feature of this meeting was that the mornings were largely given over to plenaries a total of eighteen being presented. These included con- tributions on environmental applica- tions atomic and molecular spectros- copy surface techniques and chemo- metrics. There were 167 contributed papers and 255 posters falling broadly into these categories but also included were many on sample preparation techniques and the use of spectros- copic detectors coupled directly to either preconcentration or chromato- graphy systems.An important part of the contem- porary CSI meetings are the pre- and post-symposia. Three were organized in Norway on the following Graphite June 9th-l4th 1991 Atomizer Techniques; Measurements of Radionuclides after Chernobyl; and Speciation of Elements in Environ- mental and Biological Sciences. Large numbers of delegates attend these meetings and they are undoubtedly major contributors to the success of the over-all event. There is however some evidence that many scientists attend only the peripheral meetings and this undoubtedly detracts from the main event.Traditionalists may Sir Alan Walsh receives his award fiom Adam HulanickiJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 199 1 VOL. 6 41 5 regret this but it certainly reflects trends elsewhere where specialist meetings have grown at the expense of those covering a broad range of sub- jects. Future CSI organizers will have to consider this point carefully. Cer- tainly those of us concerned with the next CSI in York will try to strike an appropriate balance. Perhaps some time in the future an organizing com- mittee will offer an entirely decentral- ized CSI but then will it be the CSI? A new event departure at this CSI was the introduction of a CSI Award for major scientific contributions to analytical spectroscopy. The recipient was Sir Alan Walsh and there were tributes from L.R. P. Butler P. Lar- kins and R. Sturgeon. Sir Alan’s scien- tific achievements are well known but we heard of a humble man whose infectious enthusiasm and advocacy helped to bring atomic absorption spectrometry to the benefit of the analytical community and the world at A detailed discussion of the week’s events held at an informal meeting near Bergen harbour large. One story told of how in the very early days of atomic absorption Awaiting the train to Flam during the Wednesday excursion Admiring the scenery. Left to right Mikhail Bolshov Adam Hulanicki Manfred Gras- serbauer and Zhaolung Fang A welcome stop on the coach journey back to Bergen. Left to right Yngvar Thomassen (conference organizer) Ian Brindle Julian Tyson and Helen Crews On board the catamaran.Left to right Richard Ediger Jim Crighton John Dean Sheryl Whitewood Barry Sharp Sam Houk and Carmen Huie416 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 1991 VOL. 6 When the dancing had to stop there was always the scenery to admire and the ramp was an ideal vantage point. Lejt to right Sheryl Whitewood Phil Riby Debbie Bradshaw Joanne King Ian Brindle and Mike Hinds Definitely the stars of the show Sir Alan and Lady Walsh enjoying the dancing at the Conference Farewell Party The transport really was a car ferry but that didn’t stop anyone from enjoying themselves The US contingent however were a close second when it came to putting on a show. Left to right Dorothy Barnes Susan and Gary Hieftje the life of a young boy suffering from Mg deficiency was saved following an analysis of his blood. A fitting tribute to this most humane of men.But what now? Speaking personally I do hope that future organizers will not feel obliged to make an award lest they devalue those that have gone before or burden their committees with a ‘whose turn is it next?’ decision. The city of Bergen is situated on Norway’s spectacular West Coast where a never ending vista of sea Gords and mountains capture both the eye and the imagination. Several ex- The North American ‘Spectroscopists’ Choir singing Rudolfthe Red Nosed Reindeer at the Tuesday evening cheese and wineJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY SEPTEMBER 199 1 VOL. 6 417 cursions were available to cater for all tastes the most popular being the Norway in a Nutshell tour.Delegates were taken by train through deep valleys hiding under snow-capped mountains past thundering waterfalls and tumbling rivers to the town of Ham. Here we boarded a catamaran which took us along the Aulandsfjord and into the Naeroyfjord one of the narrowest in Western Norway. The scenic tour continued by coach follow- ing roads that clung precipitously to rock ledges hewn from the mountain- sides which plunged into the cold blue water. I was strongly reminded of the West Coast of Scotland but the scale was larger and the alpine architecture gave the scene a fairyland feeling. Just the place to meet a troll one of Norway’s mythical gremlins and well known to users of scientific instru- ments everywhere.In addition to the excursions there was opportunity to sample Norway’s musical and cultural heritage with the music of Grieg as the focal point. Music of a different kind provided the entertainment at the final social event. For this the organizers hired a car ferry for an evening tour of the waterways around Bergen. The open air car deck provided the dance floor whilst in the saloons plentiful supplies of prawns and beer kept the delegates fuelled for the evening’s activities. Purists might regard steel plating as only suitable for tap dancing but analytical spectroscopists are necessa- rily a hardy race and there were some noteworthy performances. Not all of which were necessarily related to the dancing. And so to York where you are invited to attend the XXVIII CSI on June 29th-July 4th 1993. The confer- ence will be held at the University of York a modem campus offering excel- lent facilities on a compact site. The scientific programme will be organized into four main sessions dealing with Tibor Kantor leading the East European Choir in response (a few extras helped out including on the far right Pat Styris) atomic molecular and mass spectro- metry and surface science. Days will begin with a plenary session and then divide into four parallel streams each beginning with an invited lecture. Afternoon sessions will begin in a similar fashion but the remainder of the afternoon will be given over to poster presentations. There will again be a series of pre- and post-symposia and also workshops. The list of these is not yet complete but electrothermal atomization inductively coupled plasma mass spectrometry glow dis- charge spectrometry data transfer in spectroscopy and chemometrics will be included. The ancient walled city of York is full of attractions for the tourist York Minster the largest Gothic cathedral in Northern Europe; the Castle Mu- seum; the Jorvik Viking Centre; the National Railway Museum; and many more. It also provides excellent shop- ping areas and is a centre for the antiquarian book trade. Close to the city country houses such as Castle Howard and Skipton Castle are open to the public. The Yorkshire moors and the many attractive towns and villages of the Yorkshire coastline are also nearby. An aim of the Organizing Commit- tee is to keep costs to a minimum in order to enable as many scientists and students as possible to attend. For this reason the conference will be offered at a price which includes accommoda- tion in the University halls of resi- dence. If you require further informa- tion this is available from the Con- ference Secretariat Department of Chemistry Loughborough University of Technology Loughborough Lei- cestershire LE11 3TU UK. Barry L. Sharp Loughborough University of Technology Lough borough UK