A frequency-domain approach to molecular photoionization via driven Schrödinger equation

This work extends the formalism introduced in a previous publication [T. Marx and S. I. Bokarev, Phys. Rev. A 106, 032806 (2022)] and provides a comprehensive framework for predicting molecular photoelectron spectra. This method employs a frequency-domain approach, formulated as a driven inhomogeneous Schrödinger equation under first-order perturbation theory with outgoing boundary conditions. It is shown to be analytically equivalent to Fermi’s golden rule approach while offering a distinct physical interpretation tied directly to the measured photocurrent. The formalism incorporates detailed light-matter interactions, yielding unique solutions. The implementation strategy is discussed in depth, emphasizing computational efficiency and flexibility. The results are validated through comparisons with experimental data and other theoretical methods for atomic and small molecular systems and analytically solvable models.