Comparative study of photoionization of atomic hydrogen by solving the one- and three-dimensional time-dependent Schrödinger equations* *Project supported by the National Natural Science Foundation of China (Gant Nos. 12074265, 11804233, and 11575118), the National Key Research and Development Project of China (Grant No. 2017YFF0106500), the Natural Science Foundation of Guangdong, China (Grant Nos. 2018A0303130311 and 2021A1515010082), and the Shenzhen Fundamental

Abstract

We develop a numerical scheme for solving the one-dimensional (1D) time-dependent Schrödinger equation (TDSE), and use it to study the strong-field photoionization of the atomic hydrogen. The photoelectron energy spectra obtained for pulses ranging from XUV to near infrared are compared in detail to the spectra calculated with our well-developed code for accurately solving the three-dimensional (3D) TDSE. For XUV pulses, our discussions cover intensities at which the ionization is in the perturbative and nonperturbative regimes. For pulses of 400 nm or longer wavelengths, we distinguish the multiphoton and tunneling regimes. Similarities and discrepancies between the 1D and 3D calculations in each regime are discussed. The observed discrepancies mainly originate from the differences in the transition matrix elements and the energy level structures created in the 1D and 3D calculations.