A comparative study of the resonance Raman effect in linear polyenes: Conjugation length model, GF-formalism and amplitude mode model

Abstract

The conjugation length model, the amplitude mode model and the effective conjugation coordinate model for resonance Raman spectra are compared using a very simple system of a linear Peierls chain. The Hamiltonian used was Hückel-type with σ-compressibility. Vibrational frequencies, vibrational coupling constants, electronic transition energies and transition matrix elements can be evaluated explicitly for finite and infinite chains in each of the three models. In this way we can quantitatively evaluate for which specific problems the individual methods apply and for which they fail.