MULTIPHOTON ABOVE-THRESHOLD DETACHMENT BY INTENSE LASER-PULSES - A NEW ADIABATIC APPROACH

We present a new adiabatic approach for non-perturbative treatment of multiphoton above-threshold detachment (ATD) in intense laser pulses. The electron energy distributions for the pulse detachment are express ed via the detachment transition amplitudes in the monochromatic field s, and the latter are calculated with the help of the adiabatic theory based on the smallness of the laser frequency compared with the elect ron affinity or ionization potential. The theory is applied to the fir st study of the pulse shape effects on the multiphoton ATD of the nega tive ion H- by 10.6 mu m radiation. Two pulse shapes are considered: a Gaussian pulse and a square pulse with smooth edges. We present the a ngle-resolved as well as angle-integrated ATD electron energy distribu tions. They contain oscillatory satellite structures to the main peaks due to interference of the electrons detached on the rising and falli ng edges of the pulse. Simple analytical formulae describing these sub peak structures are also presented.