ISSN:0005-9021    

DOI:10.1002/bbpc.19740780202

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780203

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractRecent progress in experimental techniques has made possible the detailed study of the molecular dynamics of energy‐rich polyatomic species. The development of more sensitive tools enables us to consider such questions as the lifetime distribution, the branching ratio for alternative decay modes and the energy disposal in the dissociation products.These deeper probes into the dynamics have led to a better understanding of the theory of the formation and decay of unstable intermediates. We review a unified point of view which covers both unimolecular and bimolecular collision phenomena.An important recent diagnostic tool is the distribution of energy among the dissociation products. We consider a theory of such distributions which will enable us to correlate and codify the existing data, with particular emphasis on diviations from the RRKM predictions. A measure of the deviation is provided by the introduction of the concept ofentropythereby establishing a link between non‐equilibrium statistical mechanics and the evolution of energy‐rich super‐mo

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780204

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractAb initioSCF and CI methods are applied to the calculation of reaction surfaces of various kinds, principally electrocyclic interconversions and bimolecular additions involving free radical species. It is pointed out that qualitative concepts can be very helpful in organizing the requisite geometry search in such calculations, provided of course the electronic configurations of the systems involved are known. From a more quantitative standpoint it is asserted that the SCF method by itself is not generally sufficient in such work to accurately determine basic energy relationships between reactants, products and their respective activated complexes or intermediates but that CI techniques which are quite practical at this time are very capable of improving upon this situation by adequately balancing the correlation energy errors wherever they exist.

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780205

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractThis report is an informal summary of molecular beam spectroscopy conducted in our laboratory. The work was done in most part by T. Dyke, B. J. Howard and S. Novick, and has been published elsewhere as noted.

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780207

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractThis paper briefly reviews recent studies of the reactions of fluorine atoms with unsaturated hydrocarbons by the method of crossed molecular beams. Dynamic features of decompositions of chemically activated radicals and the information on the efficiency of intramolecular energy transfers are derived from measurements of the angular distribution of the products and the recoil energy spectrum of products.

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780208

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractThe reactionswere investigated with respect to the energy and angular distributions of the product‐ions at collision energies between 0.54 and 13.3 eV (cm‐system). An intermediate complex CH4+(or CH2D2+) is formed with a high cross section at low energies which decays into the reactants and products with a ratio of 1:2. The intensity distribution of the CH3+ion in the velocity vector diagram indicates that the transition state of the dissociating complex acts as a spherical top and decays isotropically in space. The CH3+ion is often formed with rotational excitation, CH2D+and CD2H+are formed with equal abundance at low energies. The relative abundance of CH2D+at first increases with energy and simultaneously preferred forward scattering of this ion is observed. This corresponds to the transition to a stripping process. Beyond 5.5 eV, the CH2D+abundance decreases because of the preferred formation of CHD++ H + D. The relative abundance of CD2H+rapidly decreases with increasing energy. The intensity distribution, however, remains isotropic around the center of mass. CHD+is preferentially scattered into the forward direction at high energies. Below about 1 eV, a small part of the reaction enthalpy is transformed into translational energy of the products. With increasing energy, the translational exoergicity becomes increasingly negat

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780209

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractContinuous wave lasers have been employed in gas phase microwave optical double resonance (MODR) experiments. MODR spectroscopy combines the high resolution of microwave spectroscopy with the high sensitivity to transient molecules of optical spectroscopy. Detectability of MODR effects under weak (linear) and strong (nonlinear) optical pumping conditions is discussed. Experiments are described in which the 496.5 nm line of an Ar ion laser and a tunable, cw dye laser are used to observe fourteen microwave rotational transitions in the X1Σ (ν = 0,1) and A1Σ (ν = 0‐5) states of138Ba16O and one transition in the A1Σ (ν = 1) state of137Ba16O. Partially deperturbed rotational constants for BaO A1Σ areB(ν) = 0.25832(2)‐0.001070(5) (ν + 1/2) cm−1. A description is given of the cw dye laser and of the procedure for tuning the laser to coincide with any desired rotational line of the BaO A1Σ‐X1Σ transition. A wide range of metal oxides, halides and hydrides have been produced under conditions suitable for

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780210

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractIn an elementary gas‐phase atom‐transfer reaction, A + BC → AB + C, a lower bound to the dissociation energy of the AB molecule can be deduced from a knowledge of the dissociation energy of the BC molecule and from the knowledge of the highest internal state of the AB product that is populated by the reactive collision process. This latter information may be obtained spectroscopically either from detection of AB chemiluminescence or from detection of the AB product through laser‐induced fluorescence. These two methods are illustrated for the elementary reactions Al + O3and Al + O2, from which lower bounds are derived forD00(AlO) of 5.13 ± 0.06 eV and 5.23 ± 0.04eV, res

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780211

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY

摘要:

AbstractThe free radicals known, or suspected to be present in the earth's stratosphere have been listed by Garvin and Hampson [1] and include O, O2, SO, H, OH, HO2, CH, CHO, CH3, CH3O, CH3O2, NH, NH2, HNO, NO, NO2, NO3. In the urban troposphere near ground level, this list can be greatly expanded to include many species resulting from reactions of these simple radicals with reactive hydrocarbons. Since the economical control of air pollution requires a detailed knowledge of the chemical kinetics involved in removal of stable pollutant molecules from the air, it is desirable ultimately to be able to measure the concentrations and rate constants of all such reactants. I have selected from this list the two most abundant, polar atmospheric free radicals, NO and NO2for discussion. The ground states of NO,2π and of NO2,2A1, qualify both molecules as free radicals. These molecules pollute the urban atmosphere and the stratosphere and the debates about the amounts in which they are present have precipitated major controversies in the United States and elsewhere. My purpose is to present the nature of the tropospheric problem of NO and NO2(known collectively in the trade as NOx) why their measurement is important, the current state of the art and finally some of the newer approaches to the solution to the problem in terms of the basic Federal legislation in the United States, the Clean Air Act

ISSN:0005-9021    

DOI:10.1002/bbpc.19740780212

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1974

数据来源: WILEY