Reference Force Field and CDW Amplitude of Mixed-Valence Halogen-Bridged Pt Complexes

TL;DR

This study investigates electron-phonon interactions in mixed-valence halogen-bridged platinum complexes using infrared and Raman spectroscopy, providing insights into their force fields and charge density wave amplitudes.

Contribution

It introduces a detailed analysis of electron-phonon coupling and constructs a reference force field for mixed-valence platinum chain complexes, linking optical data to microscopic parameters.

Findings

Quantitative estimates of e-ph coupling constants.

Correlation between Pt-Pt distance and CDW amplitude.

Validation of the phenomenological model against optical data.

Abstract

The spectroscopic effects of electron-phonon coupling in mixed-valence chlorine-bridged Pt chains complexes are investigated through a parallel infrared and Raman study of three compounds with decreasing Pt-Pt distance along the chain. The e-ph interaction is analyzed in terms of the Herzberg-Teller coupling scheme. We take into account the quadratic term and define a precise reference state. The force field relevant to this state is constructed, whereas the electronic structure is analyzed in terms of a simple phenomenological model, singling out a trimeric unit along the chain. In this way we are able to account for all the available optical data of the three compounds, and to estimate the relevant microscopic parameters, such as the e-ph coupling constants and the CDW amplitude.