Quantum chemical study of electron-phonon interaction in crystals

Study of the interaction of the electromagnetic radiation with nonlocal potentials and the electron-phonon interaction is motivated by its key role in non-classical phenomena in dielectrics and semiconductors. Actual in second quantization is decoupling of the undesirable mixture of electronic and phonon birth/annihilation operators and obtaining the effect of radiation in presence of the nonlocal potentials. Here we transform an arbitrary effective electron-phonon Hamiltonian in two matrices - the matrix of a new interaction Hamiltonian and the matrix of the transformation. For a particular effective Hamiltonian formulated in second quantization these two matrices outline a starting point to decouple the electron-phonon interaction by transformation of the lattice Hamiltonian to a purely electronic one available for wave function and atomic orbital approaches. The impact of external electromagnetic radiation is incorporated through the birth/annihilation operators. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim