Charge-transfer excitations in partly-inoic complexes

Abstract

The Mulliken dimer of admixed DA and D⁺ A⁻ Configurations requires extensive generatlization to solid complexes of π-donors (D) and π-acceptors (A) with many more configurations. Diagrammatic valence-bond techniques yield correlated crystal states that rationalize the cohesive energy of party-ionic (q~0.05) orgainic complexes, lead naturally to a q-dependent kinetic energy contribution, and produce charge-transfer (CT) excitations and intensities that differ signigicantly from dimer results for intermediate ionicity. CT. spectra in solids are sentitive to interstrand Coulomb interactions that stabilize intermediate q relative to both natural and ionic ground states.