Theoretical interpretation of electro-absorption spectra for intense optical transitions

摘要: The interaction of a light wave with molecular crystal subjected at the same time to influence static electric field is analyzed. coupling radiation described in terms classical electrodynamics, transition moments being represented by oscillating dipoles. parameters that enter equations motion (transition energy and oscillator strength), modified field, are derived from corresponding zero-field values using quantum-mechanical perturbation theory. Subsequently, field-induced change absorption spectrum electro-absorption (EA) signal calculated as difference between spectra nonzero zero modulating field. approach valid for any allowed transition, irrespective its intensity. results demonstrate that, while very intense transitions exhibit substantial peculiarities (such orientational dispersion polariton effects), relationship always same, regardless strength; specifically, EA nondegenerate Frenkel exciton follows first derivative band. These conclusions discussed context recent literature on this subject.