Above-threshold multiphoton detachment of H{sup {minus}} by two-color laser fields: Angular distributions and partial rates

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.51.4797· OSTI ID:64022

Telnov, D A; Wang, J; Chu, S ^[1]

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1. Department of Chemistry, University of Kansas, Lawrence, Kansas 66045 (United States)

We present a general nonperturbative formalism and an efficient and accurate numerical technique for the study of the angular distributions and partial widths for multiphoton above-threshold detachment in two-color fields. The procedure is based on an extension of our recent paper for one-color detachment, and the many-mode Floquet theory. The generalization of this procedure is performed for both cases of commensurable and incommensurable frequencies of the two-color fields. The procedure consists of the following elements: (i) Determination of the resonance wave function and complex quasienergy by means of the non-Hermitian Floquet Hamiltonian formalism. The Floquet Hamiltonian is discretized by the complex-scaling generalized pseudospectral technique recently developed [J. Wang, S.-I Chu, and C. Laughlin, Phys. Rev. A 50, 3208 (1994)]. (ii) Calculation of the angular distribution and partial widths based on an exact differential formula and a procedure for the rotation of the resonance wave function back to the real axis. The method is applied to a nonperturbative study of multiphoton above-threshold detachment of H{sup {minus}} by 10.6-{mu}m radiation and its third harmonic (the commensurable case). The results show strong dependence on the relative phase {delta} between the fundamental frequency field and its harmonic. For the intensities used in calculations (10{sup 10} W/cm{sup 2} for the fundamental frequency, 10{sup 8} and 10{sup 9} W/cm{sup 2} for the harmonic), the total rate has its maximum at {delta}=0 and minimum at {delta}={pi}. However, this tendency, though valid for the first several above-threshold peaks in the energy spectrum, is reversed for the higher-energy peaks. The energy spectrum for {delta}={pi} is broader, and the peak heights decrease more slowly compared to the case of {delta}=0. The strong phase dependence is also manifested in the angular distributions of the ejected electrons.

• OSTI ID: 64022
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 6 Vol. 51; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANGULAR DISTRIBUTION
ELECTRON DETACHMENT
HYDROGEN IONS 1 MINUS
KINETICS
MULTI-PHOTON PROCESSES
PHOTON-ION COLLISIONS
THRESHOLD ENERGY