Study in momentum space of phase-dependent effects on ionization of
hydrogen atom interacting with short infrared laser pulses
Abstract
We examine above-threshold ionization spectra of model atomic hydrogen
in short infrared laser pulses by solving the one-electron
time-dependent Schr\“odinger equation in momentum space.
To bypass the difficulty of solving the time-dependent
Schr\”odinger equation with the interacting nonlocal
Coulomb potential, we have recently formulated an alternative
\emph{ab initio} approach [Ongonwou et al. Annals of
Physics {\bf 375}, 471 (2016)], which is relied on
the expansion of the atomic wavefunction and the interacting nonlocal
Coulomb potential on a discrete basis set of Coulomb Sturmians in
momentum space. As far as short infrared laser pulses are concerned, we
have numerically evaluated the photoelectron momentum distributions,
angular distributions and bound states populations. The results obtained
from our accurate new computationally method are compared against
predictions of other time-dependent calculations in the literature. This
new theoretical model shows its sensitivity to the carrier-envelope
phase of the laser pulse and captures the left-right dependence of the
emitted photoelectrons momentum and angular distributions. More
precisely, short pulses manifest significant dependence of the
differential ionization probability on carrier-envelope phase of the
laser pulse and broken forward-backward symmetry in the angular
distributions.