|
1. |
The evaluation of the one-centre integrals in the semi-empirical molecular orbital theory† |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 97-109
Luigi Oleari,
Lorenzo Di Sipio,
Gianni De Michelis,
Preview
|
PDF (592KB)
|
|
摘要:
An expression is given which fairly accurately provides valence-state energies. It is shown that one can formally attribute the meaning of the one-centre integrals to the coefficients in such an expression. In this way one also obtains the criteria of Pariser and Parr. Moreover, if one introduces such semi-empirical integrals in the expression which gives the vertical ionization potentials and electron affinities, one obtains the corresponding experimental values. On the basis of these facts usage of such semi-empirical integrals in the M.O.-L.C.A.O. theory is proposed. A discussion of the advantages and the limitations of its application is made.
ISSN:0026-8976
DOI:10.1080/00268976600100161
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
2. |
The spectra and electronic structure of tetrahedral ions |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 111-129
Luigi Oleari,
Gianni De Michelis,
Lorenzo Di Sipio,
Preview
|
PDF (842KB)
|
|
摘要:
An S.C.F.-M.O.-L.C.A.O. calculation in the Roothaan-Popie scheme, using the Pariser-Parr approximations, has been carried out for the ions [CrO4]--and [MnO4]-.
ISSN:0026-8976
DOI:10.1080/00268976600100171
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
3. |
A Nuclear Magnetic Resonance Study of Mercury Dimethyl |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 131-140
K.A. McLauchlan,
D.H. Whiffen,
L.W. Reeves,
Preview
|
PDF (521KB)
|
|
摘要:
The1H,199Hg and13C spectra of the more common of the isotopic species occurring in natural abundance in mercury dimethyl have been studied. The proton spectra were observed directly whilst the199Hg and13C spectra were measured indirectly by a double resonance method involving observation in the proton region. A hitherto unreported long range coupling of magnitude 0·44±0·02 c/s was observed between the methyl protons and new values were obtained for the directly bonded13C-H coupling, ± 129·6±0·1 c/s, and for the geminal199Hg-12C-H coupling, ± 101·9±0·1 c/s. The relative signs of these couplings, together with the sign and magnitude of the directly bonded199Hg-13C coupling, ±689±2 c/s, were determined by experiments on the 0·33 per cent abundant species H313C199Hg-12CH3. The magnitude of the199Hg-13C coupling is discussed in terms of the correlation between reduced coupling constants and atomic number. The vicinal13C-Hg-12CH3coupling appears to be zero.
ISSN:0026-8976
DOI:10.1080/00268976600100181
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
4. |
Non-aqueous solutions of electrolytes |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 141-153
M.St.J. Arnold,
K.J. Packer,
Preview
|
PDF (697KB)
|
|
摘要:
Measurements of the spin-lattice relaxation time,T1, for the75As nucleus are presented for solutions of potassium hexafluoroarsenate in acetonitrile, acetone, ethyleneglycol-dimethylether and diethyleneglycol-dimethylether. Viscosity and density data are given for each series of solutions. Plots of (T1)-1against viscosity are linear for each solution. The relaxation is interpreted in terms of the fluctuating quadrupole coupling of the75As nucleus, the mean square value of which is constant over the whole concentration range for a given solvent. Possible origins of the electric field gradients at the75As nucleus are discussed in the light of this and earlier work on similar systems. The viscosity and density data are used to obtain a set of ‘ solvation numbers ’.
ISSN:0026-8976
DOI:10.1080/00268976600100191
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
5. |
Molecular motion in liquid benzene by nuclear magnetic resonance |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 155-161
J.G. Powles,
R. Figgins,
Preview
|
PDF (422KB)
|
|
摘要:
The proton spin-lattice relaxation time,T1, has been measured for a series of mixtures of benzene in perdeuterobenzene for the liquid in equilibrium with its vapour over the temperature range from below the normal freezing point up to the critical temperature. The two contributions toT1due to interactions within the molecule (T1 intra) and between molecules (T1 inter) have been separated and are found to be very different in magnitude and in variation with temperature. The variation and magnitude ofT1 intercorrelates well with other translational motion dependent properties such as self diffusion and viscosity. The correlation ofT1 intrawith other re-orientation dependent properties such as deuteronT1and Rayleigh scattering is poor.
ISSN:0026-8976
DOI:10.1080/00268976600100201
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
6. |
The calculation of rainbow scattering cross sections |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 163-173
R.J. Munn,
FrancisJ. Smith,
Preview
|
PDF (541KB)
|
|
摘要:
A method is described for calculating low resolution differential cross sections near the rainbow angle. It is used to calculate a table of the positions of the principal maxima and minima in the rainbow structure for a 6–12 potential for different rainbow angles and different values of the de Boer parameter, Λ*, between 0·1 and 0·01. A comparison with similar results obtained using Ford and Wheeler's approximation shows that the latter is quite accurate for determining the energy parameter, ε, but is usually unsatisfactory for determining the distance parameter, σ. A method is given for determining both of these parameters more accurately from the values in the table and a further table is given with which it is possible to determine which region of the real potential is being fitted by the 6–12 potential. It is found that the rainbow structure in determined only by the attractive part of the potential close to the minimum and is independent of the shape of the potential inside the minimum.
ISSN:0026-8976
DOI:10.1080/00268976600100211
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
7. |
An extended Wolfsberg-Helmholz calculation on CuF6-4 |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 175-181
Helge Johansen,
C.J. Ballhausen,
Preview
|
PDF (337KB)
|
|
摘要:
A semi-empirical calculation of the orbital energy levels of CuF6-4has been performed using the Wolfsberg-Helmholz approximations as extended by Ballhausen and Gray. The calculated value of 10Dqis rather insensitive to the initial assumptions and is in good agreement with experiments. The location of the ‘non-bonding’t1ulevel is on the other hand found to be very dependent upon the atomic wavefunctions used.
ISSN:0026-8976
DOI:10.1080/00268976600100221
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
8. |
A MO calculation of the static Jahn-Teller effect in CuF6-4 |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 183-189
C.J. Ballhausen,
Helge Johansen,
Preview
|
PDF (279KB)
|
|
摘要:
Using the LCAO-MO wavefunctions estimated by an extended Wolfsberg-Helmholz method, the first order static Jahn-Teller effect in CuF6-4has been calculated. The bond length difference between the long and the short bonds is found to be some 0·2å, in reasonable agreement with experiment.
ISSN:0026-8976
DOI:10.1080/00268976600100231
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
9. |
Study of an external spherical reference system for N.M.R. spectroscopy |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 191-200
D.J. Frost,
G.E. Hall,
Preview
|
PDF (471KB)
|
|
摘要:
More accurate equations than previously used to describe a non-perfect spherical reference system are given, and experiments to confirm them described. When such a system is used to measure chemical shifts, there should be a correction due to the magnetic susceptibility of the material from which the sphere is made, as well as corrections due to the susceptibilities of the solutions. It is also shown that the change in magnetic field strength, caused by insertion of a sample into the pole gap of a magnet, may be significant in certain circumstances. The ‘substitution’ method of external referencing must therefore be used with care.
ISSN:0026-8976
DOI:10.1080/00268976600100241
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
10. |
Temperature effects on charge transfer fluorescence spectra and mechanisms of charge transfer interactions in the excited electronic state |
|
Molecular Physics,
Volume 10,
Issue 2,
1966,
Page 201-202
Noboru Mataga,
Kiyoshi Ezumi,
Tadashi Okada,
Preview
|
PDF (116KB)
|
|
ISSN:0026-8976
DOI:10.1080/00268976600100251
出版商:Taylor & Francis Group
年代:1966
数据来源: Taylor
|
|