Molecular Orbital Calculations of the Lower Excited Electronic Levels of Benzene, Configuration Interaction Included

Abstract

The lower excited π-electron levels of benzene are calculated by the non-empirical method of antisymmetrized products of molecular orbitals (in LCAO approximation) including configuration interaction. All configurations arising from excitation of one or two electrons from the most stable configuration are considered, and all many-center integrals are retained. The results are in better agreement with experiment and valence-bond calculations than those obtained previously by Craig in a calculation neglecting many-center integrals. Configuration interaction is found to change the order of the 1B1u and 1E2g states but leave unchanged the order of the 3B1u and 3B2u states, in agreement with the assignments 1A1g—3B1u and 1A1g—1E2g for the experimental bands at 3.8 and 6.2 ev.

Correlated Dirac fermions on the honeycomb lattice studied within cluster dynamical mean field theory

“…2 In the case of a benzene molecule, the on-site Hubbard interaction was estimated to be U ≈ 17 eV. 24 In contrast, in polyacetylene this value is reduced to about U ≈ 10 eV, with a hopping interaction t = 2.5 eV. 25 The ratio U/t ≈ 4 would then be slightly larger than the critical Coulomb interaction found here and in Refs.…”

Low-Density Ferromagnetism in Biased Bilayer Graphene

“…Except at very low temperatures, there is a linear dependence of U c on T . It is clear that at low temperatures, T ≃ 0.2 K, the value of U c is smaller than the estimated values of U for carbon compounds [35,36].…”

Dynamical susceptibilities of the Falicov-Kimball model with correlated hopping: general approach

“…The importance of the correlated hopping in ferromagnetism was shown in [15][16][17][18]. Other reasons for considering the correlated hopping are based on a substantial Coulombian interaction between electrons, reported for some materials [19,20], dynamical part of which can be approximated by correlated hopping. When correlated hopping is present, the self-energy becomes non-local, and, as it was shown in earlier investigations [21], this non-locality can be presented as the next-nearest-neighbors hopping contribution to self-energy.…”