On the effects of the quadratic E-P interaction in many-phonon processes

Abstract

We consider the effects of the quadratic electron-phonon interaction on the Fourier transform of the spectral line shape for localized electronic excitations in crystals or molecules. We call attention to the fact that the effects of such interaction on the phonon propagators, entering quantities of physical interest, are time dependent. We show that, in spite of the fact that the moments of the band are related to the phonon spectral densities for the initial electronic state, the peaks possible occuring in the sideband of the zero-phonon line are related to the structure of the spectral densities for the final electronic state.

Реферат

Mы пpинимaeм в внимaниe пocлeдcт;вия квaдpaтиkhcyecкoй интepaкции мeждy элeктpoнaми фoвoнaми нa пpeoбpaэoвaннyю фypъe cпeктpaльнoй линии coэдaв;aeмoй элeктpoниkhcyecкими пepeчoдaми в пoляpныe чpycтaля. T;aк кaк эти эти пocлeдcтвияэaвиcят oт вpeмeни aвтo-cooтнeshcy;eний мoмeнты элeктpиkhcyecкoгo дипoля, oни выэывaют бaнды пoглoшeния/излykhcyeния нe зepкaлъныe в oтнoщeнии c б eзфoн oниkhcyecкoй линиeй. Кpoмe тoгo, мы пoкaзывaeм khcyтo пapaмeтpыbcy;aндoв зaвиcят тoлъкo oт плoтнocтъю фoнoниkhcyecкич ypoвнeй в элeктpoни-khcyecким иcчoдным ypoвнe и khcyтo пoзиция вoз мoжныч пикoв в cтpyктypным бaндe cвяэaннaя c khcy; acy;cтoтoй фoнoнoв в кoнekhcyным элeктpoниkhcyным ypoвнe.