Quantum Treatment of Continuum Electrons in the Fields of Moving Charges...

An exact three-dimensional (3D) quantum mechanical treatment is presented for the evolution of
continuum electrons in the fields of moving ions. The novel method introduced here allows one to
propagate the continuum electrons to asymptotically large internuclear distances and obtain stable
as well as well-converged ejected electron momentum spectra. As a result, our computations resolve
long standing controversies concerning top-of-barrier, superpromotion and cusp electron momentum
distributions. While the method is employed for proton impact ionization of atomic hydrogen, it
is general and readily applied to any problems involving electron motion in the presence of time-
dependent external fields.