THEORETICAL STUDIES ON THE ELECTRONIC SPECTRA OF SUBSTITUTED AROMATIC MOLECULES: PART II. SEMIEMPIRICAL SELF-CONSISTENT FIELD CALCULATIONS ON ANILINE

1964 ◽  
Vol 42 (1) ◽  
pp. 121-136 ◽  
Author(s):  
J. E. Bloor ◽  
P. N. Daykin ◽  
P. Boltwood
Keyword(s):  
Ionization Potential ◽  
Oscillator Strengths ◽  
Electronic Transitions ◽  
Aromatic Molecules ◽  
The Core ◽  
Consistent Field ◽  
Aniline Molecule ◽  
Self Consistent Field ◽  
Reasonable Choice ◽  
Experimental Values

The results of 14 calculations on the aniline molecule using different choices of parameters within the framework of the semiempirical SCFMO method have been carried out using an automatic Fortran 1A program written for an I.B.M. 1620 computer. It has been shown that the approximation of using the valence state ionization potential as a measure of the core integral of a heteroatomic substituent underestimates the amount of electron transfer between substituent AO and the benzene MO's. By adjusting this core integral empirically or by using a variable electronegativity MO approach it has been found possible to obtain, for the same set of parameters, agreement between experiment and theory for: the first two electronic transitions in the vapor state (4.23–4.38 ev and 5.22–5.41 ev), the change in ionization potential relative to benzene (AI = 1.54 ev), and the electron density para to the amino group (ρ4π = 1.059). It was not found possible to calculate values for the π-electron dipole moment and oscillator strengths which agreed, for any reasonable choice of parameters, with experimental values.

scholarly journals Self-consistent field, with exchange, for nitrogen and sodium

1948 ◽  
Vol 193 (1034) ◽  
pp. 299-304 ◽  
Keyword(s):  
Ionization Potential ◽  
Normal State ◽  
Wave Functions ◽  
The Self ◽  
Electron Atom ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

Wave functions for the normal configurations of neutral nitrogen and N - have been calculated by the method of the self-consistent field with exchange (Fock’s equations). To the accuracy of the approximation represented by these equations, the N - ion would be unstable and liable to auto-ionization, but it is estimated that a better approximation of the treatment of a many-electron atom would give a small positive ionization potential for N - . Revised wave functions for Na + and the normal state of neutral Na have also been calculated. Tables of results are given.

APPROXIMATE WAVE FUNCTIONS OF Pb+++ BY THE METHOD OF SELF-CONSISTENT FIELD WITHOUT EXCHANGE

1959 ◽  
Vol 37 (9) ◽  
pp. 983-988 ◽  
Author(s):  
J. F. Hart ◽  
Beatrice H. Worsley
Keyword(s):  
Common Point ◽  
Wave Functions ◽  
The Self ◽  
Decimal Digit ◽  
Hartree Fock ◽  
The Core ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Approximate Wave

The FERUT program previously described for calculating Hartree–Fock wave functions by the method of the self-consistent field has been adapted to the configuration Pb+++. Although the exchange factors were omitted, the program was extended beyond its original scope in other respects, and an assessment of the difficulties so encountered is made. It might be noted, however, that, except in the case of the 4ƒ wave function, it was possible to begin all the integrations at a common point. Initial estimates were made from the Douglas, Hartree, and Runciman results for thallium. The estimates for the core functions were not assumed to be satisfactory. The errors in the final wave functions are considered to be no more than one or two units in the second decimal digit.

Electronic structure of the first row hydrides BH, CH, NH, OH and FH. I. Ground states

1958 ◽  
Vol 248 (1252) ◽  
pp. 119-135 ◽  
Keyword(s):  
Molecular Orbital ◽  
Electron Correlation ◽  
Dipole Moments ◽  
Valence Bond ◽  
Orbital Method ◽  
Constant Amount ◽  
Consistent Field ◽  
Valence Electrons ◽  
Self Consistent Field ◽  
Experimental Values

Some recent calculations by the self-consistent field molecular orbital method are generalized to allow for electron correlation. Correlations between the motions of the valence electrons are introduced explicitly by means of configuration interaction, whilst the effects of intra-atomic electron correlation are estimated semi-empirically. Both forms of correlation, but especially the latter, are found to have a profound effect on the calculated properties of the hydrides. The total electronic energies obtained in the final calculations fall consistently above the experimental values by an almost constant amount (0.5 to 0.7 eV). The wave functions and dipole moments of the molecules are analyzed in the frameworks of both the valence-bond and molecular orbital theories.

The Study of Bond Selective Photochemistry in CH2BrCl

2013 ◽  
Vol 699 ◽  
pp. 107-110
Author(s):  
Lan Li ◽  
Zong He Li
Keyword(s):  
Configuration Interaction ◽  
Oscillator Strengths ◽  
Bond Breaking ◽  
Complete Active Space ◽  
Active Space ◽  
Hartree Fock ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

The photodissociation of chlorobromomethane (CH2BrCl) has been studied using unrestricted Hartree-Fock (UHF), configuration-interaction-singles (CIS), and complete active space self-consistent field (CASSCF) levels. The result of oscillator strengths indicate that the photochemistry reactions of CH2BrCl are processes where the n(Br)→σ*(C-Br) transition are excited to repulsive states leading to direct carbon-bromine bond breaking reactions. And the 1A’ →1A’ state is the important transition in photolysis of chlorobromomethane.

scholarly journals Results of calculations of atomic wave functions III—results for Be, Ca and Hg

1935 ◽  
Vol 149 (867) ◽  
pp. 210-231 ◽  
Keyword(s):  
Good Deal ◽  
Field Approximation ◽  
The Self ◽  
Field Calculation ◽  
The Core ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Normal States ◽  
Group 5

In two previous papers, results of calculations of approximate atomic fields and way functions, carried out to a fairly high degree of numerical accuracy by the method of the "self-consistent field," have been presented. This paper gives similar results for the normal states of three other atoms, namely, Be, Ca, and Hg, both neutral and doubly ionized. In all these cases, the "self-consistent field" calculation has been carried out both for the ion and for the neutral atom; it has not been assumed that the "core" formed by the doubly ionized atom is unperturbed by the addition of the two "valency" electrons, but the perturbation of the core on addition of the two valency electrons has been taken into account, as far as this is possible on the "self-consistent field" approximation to a many-electron atom. This perturbation is quite appreciable, especially for Hg, for which the outermost group, (5 d ) 10 , of the core is very sensitive to perturbing influences; for Ca, for which the core is inert-gas-like and has its outermost group, (3 p ) 6 , comparatively tightly bound, this perturbation was expected to be quite small; it was actually found to be a good deal larger than was expected.

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