Spectral properties of molecular oligomers. A non-Markovian quantum state diffusion approach

TL;DR

This paper investigates the spectral properties of molecular oligomers, focusing on how vibrational coupling and monomer interactions influence absorption spectra, using a novel non-Markovian quantum state diffusion method.

Contribution

It introduces a non-Markovian quantum state diffusion approach to analyze the spectral features of molecular oligomers, including J- and H-bands, considering vibrational and interaction effects.

Findings

Spectra shift with oligomer length and interaction strength.

The approach effectively describes J- and H-band formations.

Spectral line-shapes depend on vibrational coupling.

Abstract

Absorption spectra of small molecular aggregates (oligomers) are considered. The dipole-dipole interaction between the monomers leads to shifts of the oligomer spectra with respect to the monomer absorption. The line-shapes of monomer as well as oligomer absorption depend strongly on the coupling to vibrational modes. Using a recently developed approach [Roden et. al, PRL 103, 058301] we investigate the length dependence of spectra of one-dimensional aggregates for various values of the interaction strength between the monomers. It is demonstrated, that the present approach is well suited to describe the occurrence of the J- and H-bands.