Ionization of the hydrogen atom by short half-cycle pulses: dependence on the pulse duration

D. G. ARBÓ; M. S. GRAVIELLE; K. I. DIMITRIOU; K. TÕKÉSI; S. BORBÉLY; J. E. MIRAGLIA

EUROPEAN PHYSICAL JOURNAL D

SPRINGER

Lugar: Berlín; Año: 2010 vol. 59 p. 193 - 200

1434-6060

A theoretical study of the ionization of hydrogen atoms by short external half-cycle pulses (HCPs) as a function of the pulse duration, using different quantum and classical approaches, is presented. Total ionization probability and energy distributions of ejected electrons are calculated in the framework of the singly-distorted Coulomb-Volkov (SDCV) and the doubly-distorted Coulomb-Volkov (DDCV) approximations. We also performed quasiclassical calculations based on a classical trajectory Monte Carlo method which includes the possibility of tunneling (CTMC-T). Quantum and classical results are compared to the numerical solution of the time-dependent Schrödinger equation (TDSE). We find that for high momentum transfers the DDCV shows an improvement compared to the SDCV, especially in the low-energy region of the electron emission spectra, where SDCV fails. In addition, DDCV reproduces successfully the TDSE electron energy distributions at weak momentum transfers. CTMC-T results reveal the importance of tunneling in the ionization process for relative long pulses and strong momentum transfers but fails to overcome the well-known classical suppression observed for weak electric fields.