LASER EFFECTS IN PHOTOIONIZATION - SPECTRUM OF RADIATION SCATTERED RESONANTLY BY ATOMIC-HYDROGEN

The spectrum of scattered radiation was computed for an electron, bound initially in the ground state of an isolated hydrogen atom and driven resonantly by the field of a moderately intense (approximately 10(13) W(cm)-2), linearly polarized laser. A numerical solution of the time-dependent Schrodinger equation was performed for the duration of a short (approximately 30 femtosecond) laser pulse. The spectrum of radiation scattered by this transient state was determined from the autocorrelation function of the electronic acceleration defined as: C(a)(t) = integral-infinity/-infinity dt'[1s\a(t').a(t' - t)\1s]. The spectral density of emitted radiation was then S(OMEGA) = (alpha-3/3-pi) integral-infinity/-infinity dt exp(i-OMEGA-t) C(a)(t). Numerical results are presented and comparison is made with an earlier less precise formulation.