VBDFT(s): a Huckel-type semi-empirical valence bond method scaled to density functional energies. Application to linear polyenes

摘要

A semi-empirical valence bond (VB) method, called VBDFT(s), is described and applied to CnHn+2 conjugated hydrocarbons. The method is a Huckel-type VB scheme with energies scaled to density functional theory energies based on a single parameter; the matrix element lambda due to spin transposition between bonded atoms. Total energies, excitation energies, resonance and rr-bond energies are presented for the various species. The insight that can be derived from the corresponding wavefunctions is discussed. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 24]