Two-dimensional electronic spectroscopy from first principles

TL;DR

This paper introduces a first-principles computational method for simulating two-dimensional electronic spectroscopy using real-time TDDFT, incorporating vibronic effects and advanced numerical techniques for efficiency.

Contribution

It presents a novel, efficient first-principles scheme for 2D electronic spectroscopy simulation that includes vibronic effects and reduces computational complexity.

Findings

Successfully applied to molecules like benzene, pyridine, and pyrene.

Demonstrates the method's effectiveness and discusses approximation impacts.

Lays groundwork for extending to more complex systems.

Abstract

The recent development of multidimensional ultrafast spectroscopy techniques calls for the introduction of computational schemes that allow for the simulation of such experiments and the interpretation of the corresponding results from a microscopic point of view. In this work, we present a general and efficient first-principles scheme to compute two-dimensional electronic spectroscopy maps based on real-time time-dependent density-functional theory. The interface of this approach with the Ehrenfest scheme for molecular dynamics enables the inclusion of vibronic effects in the calculations based on a classical treatment of the nuclei. The computational complexity of the simulations is reduced by the application of numerical advances such as branching techniques, undersampling, and a novel reduced phase cycling scheme, applicable for systems with inversion symmetry. We demonstrate the effectiveness of this method by applying it to prototypical molecules such as benzene, pyridine, and pyrene. We discuss the role of the approximations that inevitably enter the adopted theoretical framework and set the stage for further extensions of the proposed method to more realistic systems.