Simulating pump-probe photo-electron and absorption spectroscopy on the attosecond time-scale with time-dependent density-functional theory

TL;DR

This paper extends real-time TDDFT to simulate pump-probe attosecond spectroscopy, enabling detailed interpretation of ultrafast electronic dynamics and providing new insights into electronic structure through variable pulse parameters.

Contribution

It introduces a method to simulate time-resolved pump-probe spectroscopy using TDDFT, including the effects of pulse parameters, and extends to 2D spectroscopies for large systems.

Findings

Simulation of pump-probe spectra reveals electronic dynamics.

Variable pulse parameters enhance system characterization.

Extension to 2D spectroscopy for large structures.

Abstract

Molecular absorption and photo-electron spectra can be efficiently predicted with real-time time-dependent density-functional theory (TDDFT). We show here how these techniques can be easily extended to study time-resolved pump-probe experiments in which a system response (absorption or electron emission) to a probe pulse, is measured in an excited state. This simulation tool helps to interpret the fast evolving attosecond time-resolved spectroscopic experiments, where the electronic motion must be followed at its natural time-scale. We show how the extra degrees of freedom (pump pulse duration, intensity, frequency, and time-delay), which are absent in a conventional steady state experiment, provide additional information about electronic structure and dynamics that improve a system characterization. As an extension of this approach, time-dependent 2D spectroscopies can also be simulated, in principle, for large-scale structures and extended systems.