Energy and charge-transfer dynamics using projected modes

摘要

For electron-phonon Hamiltonians with the couplings linear in the phonon operators, we constructa class of unitary transformations that separate the normal modes into two groups. The modes in thefirst group interact with the electronic degrees of freedom directly. The modes in the second groupinteract directly only with the modes in the first group but not with the electronic system. Thesetransformations can be carried out independently for different types of phonon modes, e.g.,high- versus low-frequency phonon bands. This construction generalizes recently introducedtransformations for systems exhibiting a conical intersection topology. The separation of the normalmodes into several groups allows one to develop new approximation schemes. We apply one of suchschemes to study electronic relaxation at a semiconducting polymer interface.