Threshold-Related Effects on the High Energy Plateau in Above-Threshold Detachment

Authors

Katarzyna Krajewska, University of Nebraska-LincolnFollow
Ilya I. Fabrikant, University of Nebraska-LincolnFollow
Anthony F. Starace, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

3-28-2007

Comments

Published in Laser Physics, 2007, Vol. 17, No. 4, pp. 368–375. Copyright © MAIK “Nauka /Interperiodica” (Russia), 2007. Original Text © Astro, Ltd., 2007. Used by permission. http://www.lasphys.com/lasphys.htm

Abstract

We present results of a nonperturbative Floquet study of above-threshold detachment (ATD) of the H^– and F^– negative ions. Pronounced enhancements of ATD rates in the high-energy plateau region are found as the laser field intensity passes across ponderomotively shifted multiphoton thresholds. Depending on the symmetry of the initial state (s or p symmetry), the enhancement is found to be most pronounced for even- or odd-channel closures, which is consistent with threshold laws applicable at the closing of particular multiphoton channels. Variations of ATD photoelectron angular distributions as functions of laser intensity near multiphoton thresholds are also investigated.