Theoretical Study of Spin Alignment of Organic High-Spin Molecules in Terms of VB Description

Publisher Website
Google Scholar
Abstract
Spin alignment in organic high-spin molecules and their topological isomers with both unpaired π and [sgrave] electrons has been studied by the exact numerical solutions of the valence-bond Heisenberg Hamiltonian and of the UHF calculation of the generalized Hubbard Hamiltonian. In order to clarify the main path-way of the spin correlation, the spin configurations with large coefficients have been extracted from the eigenfunctions in the ground and low-lying excited states of the Heisenberg Hamiltonian. The contributions of their spin configurations to the total spin energy have been calculated. Using this procedure, important spin configurations (important path-way of exchange correlations) of the ground and low-lying excited states have been clarified. A similar treatment can be carried out by the generalized Hubbard Hamiltonian. Thus, the VB decompositions of UHF solutions of the generalized Hubbard model have been carried out using the total α spin and total β spin densities on each carbon site in the UHF total wavefunction. The VB picture so obtained is also qualitatively in agreement with the results of the valence-bond Heisenberg Hamiltonian. The detailed mechanism in the spin alignment has been discussed in terms of the VB description by these two model Hamiltonian approaches.

This publication has 11 references indexed in Scilit: