Motional narrowing effect in one-dimensional Frenkel chains with configurational disorder

TL;DR

This paper investigates how positional disorder affects the motional narrowing effect in one-dimensional Frenkel chains, revealing distinct scaling laws compared to other types of disorder, with implications for understanding exciton dynamics.

Contribution

It provides a detailed analysis of motional narrowing in off-diagonal disorder with positional fluctuations, highlighting differences from diagonal disorder and previous models.

Findings

Distinct scaling laws for positional disorder versus diagonal disorder

Differences in motional narrowing behavior due to off-diagonal disorder

Discussion of the origin of these differences in scaling laws

Abstract

We analyze the peculiarities of the motional narrowing effect in disordered one-dimensional Frenkel chains with off-diagonal disorder, induced by uncorrelated Gaussian fluctuations in the positions of the host units. A clear difference in the scaling laws with respect to the magnitude of the positional disorder and the chain size is found, as compared to those for uncorrelated diagonal disorder as well as for off-diagonal disorder modeled by uncorrelated randomness in the nearest-neighbor couplings. The origin of such a difference is discussed in detail.