Above-threshold multiphoton detachment from the H[sup [minus]] ion by 10. 6-[mu]m radiation: Angular distributions and partial widths

Journal Article · Tue Nov 01 04:00:00 EST 1994 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.50.4099· OSTI ID:7122223

Telnov, D A; Chu, S ^[1]

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

We present a general procedure for accurate nonperturbative treatment of the angular distribution and partial widths for multiphoton above-threshold detachment (ATD) of atoms or negative ions in intense laser fields. The procedure consists of the following two steps: (1) The resonance wave function is determined by means of the non-Hermitian Floquet Hamiltonian method. The Floquet Hamiltonian is discretized by the complex scaling generalized pseudospectral method recently developed by Yao and Chu [Chem. Phys. Lett. 204, 381 (1993)]. No computation of potential matrix elements is required, and the kinetic-energy matrix elements can be evaluated analytically. (2) The angular distribution and partial rates are calculated, based on an exact differential expression, and a procedure is developed for the backrotation of the total complex resonance wave function to the real axis. The method is applied to the study of multiphoton ATD of H[sup [minus]] in strong fields at 10.6 [mu]m. An accurate one-electron model potential [Laughlin and Chu, Phys. Rev. A 48, 4654 (1993)], which reproduces the known H[sup [minus]] binding energy and the low-energy [ital e]-H(1[ital s]) elastic scattering phase shifts, is employed. At this low frequency, the resonance wave functions can be obtained efficiently and rather accurately by means of a nonperturbative adiabatic approach recently developed by Telnov [J. Phys. B 24, 2967 (1991)]. This adiabatic theory is also valid in the limit of weak fields, and its validation is justified by its agreement with the exact perturbation calculations for the seven- and eight-photon detachment of H[sup [minus]]. Detailed results for the angular distribution and partial widths for multiphoton ATD of H[sup [minus]] are presented for the moderately strong laser intensity regime (10[sup 10]--10[sup 11] W/cm[sup 2]) at 10.6 [mu]m.

• OSTI ID: 7122223
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 50:5; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ANIONS
CALCULATION METHODS
CHARGED PARTICLES
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ENERGY
FLOQUET FUNCTION
FUNCTIONS
HAMILTONIANS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
INFRARED RADIATION
IONIZATION
IONS
KINETIC ENERGY
LASERS
LEVEL WIDTHS
MATHEMATICAL OPERATORS
MATRIX ELEMENTS
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
QUANTUM OPERATORS
RADIATIONS
RESONANCE
THRESHOLD ENERGY
WAVE FUNCTIONS