DIRECT CALCULATION OF RESONANCE ENERGIES OF CONJUGATED HYDROCARBONS WITH ABINITIO MO METHODS

被引:144
作者
KOLLMAR, H
机构
[1] Lehrstuhl für Theoretische Chemie, Ruhr-Universitat
关键词
D O I
10.1021/ja00511a009
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Resonance energies of conjugated hydrocarbons were calculated as the energy difference between the ab initio SCF energy and the energy expectation value with respect to a model wave function in which the SCF π orbitals were replaced by appropriate nonresonating localized π MOS (reference state). The contributions of electron correlation and of relaxation of σ orbitals on resonance energies were also computed and found to be rather small in most cases. Since all electrons were included in the calculations, vertical and adiabatic resonance energies could be obtained. The adiabatic resonance energy of butadiene, which was computed to be about 9 kcal/mol, has partly to compensate for the unfavorable repulsion of the two nonresonating π MOs in the reference state. The resonance energies of other hydrocarbons were normalized with respect to butadiene and could thus be compared with thermochemical resonance energies. The largest molecules studied were naphthalene and azulene. The SCF calculations on the latter system gave evidence that azulene probably has a structure with bonds of alternate lengths. © 1979, American Chemical Society. All rights reserved.
引用
收藏
页码:4832 / 4840
页数:9
相关论文
共 56 条
[1]   PNO-CI (PAIR NATURAL ORBITAL CONFIGURATION INTERACTION) AND CEPA-PNO (COUPLED ELECTRON PAIR APPROXIMATION WITH PAIR NATURAL ORBITALS) CALCULATIONS OF MOLECULAR SYSTEMS .1. OUTLINE OF METHOD FOR CLOSED-SHELL STATES [J].
AHLRICHS, R ;
LISCHKA, H ;
STAEMMLER, V ;
KUTZELNIGG, W .
JOURNAL OF CHEMICAL PHYSICS, 1975, 62 (04) :1225-1234
[2]   METHODS FOR EFFICIENT EVALUATION OF INTEGRALS FOR GAUSSIAN TYPE BASIS SETS [J].
AHLRICHS, R .
THEORETICA CHIMICA ACTA, 1974, 33 (02) :157-167
[3]   RESONANCE ENERGIES OF BENZENOID HYDROCARBONS [J].
AIHARA, JI .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1977, 99 (07) :2048-2053
[4]  
BANDER A, 1962, HELV CHIM ACTA, V45, P1698
[5]   AN ELECTRON DIFFRACTION INVESTIGATION OF MOLECULAR STRUCTURE OF AZULENE [J].
BASTIANS.O ;
DERISSEN, JL .
ACTA CHEMICA SCANDINAVICA, 1966, 20 (05) :1319-&
[6]  
BECKER S, 1974, Z CHEM, V14, P440
[7]   GROUND-STATES OF MOLECULES .25. MINDO-3 - IMPROVED VERSION OF MINDO SEMIEMPIRICAL SCF-MO METHOD [J].
BINGHAM, RC ;
DEWAR, MJS ;
LO, DH .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1975, 97 (06) :1285-1293
[8]   DOUBLE-BOND FIXATION IN CONJUGATED PI-ELECTRON SYSTEMS .V. SELF-CONSISTENT FIELD CALCULATIONS FOR NONALTERNANT HYDROCARBONS AND NITROGEN HETEROCYCLES [J].
BINSCH, G ;
TAMIR, I .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1969, 91 (10) :2450-&
[10]   Ab initio SCF calculations for azulene and naphthalene [J].
Buenker, R. J. ;
Peyerimhoff, S. D. .
CHEMICAL PHYSICS LETTERS, 1969, 3 (01) :37-42