Comment on “Molecular first hyperpolarizability of push-pull polyenes: Relationship between electronic and vibrational contribution by a two-state model”

Abstract

Castiglioni, Del Zoppo, and Zerbi [Phys. Rev. B 53, 13 319 (1996)] have developed a theory that attempts to demonstrate the equality (or near equality) of electronic and vibrational first hyperpolarizabilities in push-pull polyenes. In this Comment we draw attention to a serious flaw in their argument.