Departmental Papers (MSE)

Document Type

Journal Article

Date of this Version

1963

Publication Source

Collection of Czechoslovak Chemical Communications

Volume

28

Issue

6

Start Page

1468

Last Page

1482

DOI

10.1135/cccc19631468

Abstract

The positions of the α- and β-bands in the electronic absorption spectra of twenty aromatic benzenoid hydrocarbons were calculated by the semiempirical method of limited configuration interaction in the π-electron approximation using the Huckel molecular orbitals. The agreement of the experimental and calculated values is good for the β-band whereas a systematic deviation is observed for the α-band. This deviation cannot be removed by extending the configuration interaction of the monoexcited states constructed from the molecular orbitals considered. However, the consideration of electronic repulsion enables us to explain the character of the dependences of the experimental excitation energies on the excitation energies obtained by the simple Huckel method of molecular orbitals. Using a suitable choice of semiempirical parameters different for various electronic transitions (showing no large mutual differences) yields semiempirical interpolation formulas for the; p-, α-, and β-bands which give very good agreement with the corresponding experimental excitation energies for the compounds studied.

Copyright/Permission Statement

Copyright © 1997–2016 Institute of Organic Chemistry and Biochemistry

Comments

At the time of publication, author Vaclav Vitek was affiliated with the Czechoslovak Academy of Sciences. Currently, he is a faculty member at the Materials Science and Engineering Department in the School of Engineering and Applied Science at the University of Pennsylvania.

 

Date Posted: 25 May 2016

This document has been peer reviewed.