Time-Dependent Density Matrix Renormalization Group Algorithms for Nearly Exact Absorption and Fluorescence Spectra of Molecular Aggregates at Both Zero and Finite Temperature

TL;DR

This paper develops and applies time-dependent DMRG algorithms to accurately compute absorption and fluorescence spectra of molecular aggregates at various temperatures, demonstrating high efficiency and precision.

Contribution

The authors implement TD-DMRG within a matrix product state framework for molecular aggregates, enabling nearly exact spectral calculations at zero and finite temperatures.

Findings

TD-DMRG yields highly accurate spectra compared to other methods.

The method efficiently handles vibrational and excitonic degrees of freedom.

Results show TD-DMRG is a powerful tool for molecular aggregate spectroscopy.

Abstract

We implement and apply time-dependent density matrix renormalization group (TD-DMRG) algorithms at zero and finite temperature to compute the linear absorption and fluorescence spectra of molecular aggregates. Our implementation is within a matrix product state/operator framework with an explicit treatment of the excitonic and vibrational degrees of freedom, and uses the locality of the Hamiltonian in the zero-exciton space to improve the efficiency and accuracy of the calculations. We demonstrate the power of the method by calculations on several molecular aggregate models, comparing our results against those from multi-layer multiconfiguration time- dependent Hartree and n-particle approximations. We find that TD-DMRG provides an accurate and efficient route to calculate the spectrum of molecular aggregates.