Computation of the temperature dependence of the heat capacity of complex molecular systems using random color noise

TL;DR

This paper introduces a novel method using Langevin equations with low frequency color noise to accurately compute the temperature-dependent heat capacity of complex molecular systems, capturing quantum effects.

Contribution

It presents a new approach that models quantum thermalization effects in molecular systems through colored noise in Langevin dynamics.

Findings

Accurately reproduces temperature evolution of specific heat in carbon nanotubes.

Models partial thermalization of high-frequency vibrations.

Demonstrates the effectiveness of color noise in molecular heat capacity calculations.

Abstract

We propose a new method for computing the temperature dependence of the heat capacity in complex molecular systems. The proposed scheme is based on the use of the Langevin equation with low frequency color noise. We obtain the temperature dependence of the correlation time of random noises, which enables to model the partial thermalization of high-frequency vibrations, which is a pure quantum effect. By applying the method to carbon nanotubes, we show that the consideration of the color noise in the Langevin equation allows to reproduce the temperature evolution of the specific heat with good accuracy.