Ionization by short UV laser pulses: secondary ATI peaks of the electron spectrum

V. D. RODRÍGUEZ; E. CORMIER; R. GAYET

Photonic, Electronic and Atomic Collisions

World Scientific Publishing Co.

Lugar: New Jersey, USA; Año: 2006; p. 206 - 213

The interaction between an atom and a short laser pulse is studied in the case where photon energies are smaller than the ionization potential and perturbation conditions prevail. A full numerical solution of the time-dependent Schrödinger equation for a hydrogen atom H(1s) reveals the existence of secondary peaks in the above-threshold ionization (ATI) spectrum. We present here an approximation that we introduced to shed light on these structures. It allows us to trace back unambiguously the new peaks to excitation of transient upper bound states followed by multiphoton absorption.