Analysis of two-dimensional photoelectron momentum spectra and the effect of the long-range Coulomb potential in single ionization of atoms by intense lasers

Abstract

Two-dimensional ͑2D͒ electron momentum distributions and energy spectra for multiphoton ionization of atoms by intense laser pulses, calculated by solving the time-dependent Schrödinger equation ͑TDSE͒ for different wavelengths and intensities, are compared to those predicted by the strong-field approximation ͑SFA͒. It is shown that the momentum spectra at low energies between the TDSE and SFA are quite different and the differences arise largely from the absence of a long-range Coulomb interaction in the SFA. We further found that the low-energy 2D momentum spectra from the TDSE exhibit ubiquitous fanlike features where the number of stripes is due to a single dominant angular momentum of the low-energy electron. The specific dominant angular momentum in turn has been found to be decided by the minimum number of photons needed to ionize the atom only. The electron momentum spectra predicted by models modified from the SFA are also examined and found to lack the fanlike features as in the SFA.

Fine structures in the intensity dependence of excitation and ionization probabilities of hydrogen atoms in intense 800-nm laser pulses

“…The electronic wave function is also expanded in spherical coordinates where the radial functions are further expanded in terms of direct products of discrete variable representation (DVR) functions [3,22]. Using the split operator method the time propagation is integrated in the space of the energy eigenstates of atomic hydrogen.…”

Precision calculation of above-threshold multiphoton ionization in intense short-wavelength laser fields: The momentum-space approach and time-dependent generalized pseudospectral method

“…It comprises several radial stripes spreading out from the center. These stripes are induced by the long-range Coulomb potential and are related to the fact that the ATI peak is determined by one dominant partial wave in the final state [15,17]. The number of the stripes equals the angular momentum quantum number of the dominant partial wave in the final state plus one [15,17,18,63].…”

“…Extensive investigations have been performed both theoretically [11][12][13][14][15][16][17][18] and experimentally [7,12,14,[19][20][21][22][23][24][25][26][27][28][29][30][31] for a comprehensive understanding of the laser-induced atomic ATI for laser fields with wavelengths from visible lights (4×10 2 nm) to infrared radiations (1×10 5 nm). With the recent development of intense and ultrashort-wavelength free-electron lasers [32][33][34], the study of multiphoton * zyzhou@ku.edu † sichu@ku.edu processes in the high-frequency and strong-field regime becomes increasingly important [35][36][37].…”

Photoelectron momentum distributions of the hydrogen molecular ion driven by multicycle near-infrared laser pulses

“…According to the Keldysh-Faisal-Reiss model [20], such interference minima correspond to the nodes of generalized Bessel functions (associated with the Volkov wave solution) along the polar angle θ p . The number and position of interference minima in the PMD also depend on the initial state configuration from which electron is ionized [26,27].…”