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Some remarks on the core resonance integral as used in the semi‐empirical π‐electron calculations
Author(s) -
Sannigrahi A. B.
Publication year - 1972
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560060207
Subject(s) - resonance (particle physics) , spectral line , core (optical fiber) , chemistry , electron , atomic physics , computational chemistry , molecular physics , physics , quantum mechanics , optics
Abstract A simple semi‐theoretical expression for β, the core resonance integral as used in the semi‐empirical π‐èlectron calculations has been proposed. β's for some standard C C and C 0 lengths have been evaluated with the proposed formula and the calculated values are compared with those obtained by other semi‐theoretical and empirical methods. Electronic spectra of ethylene, formaldehyde, trans‐butadiene and benzene have been calculated by a Pariser‐Parr‐like semi‐empirical method with the values of β thus obtained. The calculated spectra are found to be in good agreement with the observed ones.