Multiphoton detachment of H[sup [minus]]. II. Intensity-dependent photodetachment rates and threshold behavior---complex-scaling generalized pseudospectral method

Journal Article · Sat Oct 01 04:00:00 EDT 1994 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.50.3208· OSTI ID:7203670

Wang, J; Chu, S ^[1]; Laughlin, C ^[2]

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1. Department of Chemistry, University of Kansas, Lawrence, Kansas 66045 (United States)
2. Department of Mathematics, Nottingham University, Nottingham (United Kingdom)

We extend our previous perturbative study of the multiphoton detachment of H[sup [minus]] [Phys. Rev. A 48, 4654 (1993)] to stronger fields by considering the intensity-dependent photodetachment rates and threshold behavior. An accurate one-electron model potential, which reproduces exactly the known H[sup [minus]] binding energy and the low-energy [ital e]-H(1[ital s]) elastic-scattering phase shifts, is employed. A computational technique, the complex-scaling generalized pseudospectral method, is developed for accurate and efficient treatment of the time-independent non-Hermitian Floquet Hamiltonian [ital [cflx H]][sub [ital F]]. The method is simple to implement, does not require the computation of potential matrix elements, and is computationally more efficient than the traditional basis-set-expansion--variational method. We present detailed nonperturbative results of the intensity- and frequency-dependent complex quasienergies ([ital E][sub [ital R]],[minus][Gamma]/2), the complex eigenvalues of [ital [cflx H]][sub [ital F]], providing directly the ac Stark shifts and multiphoton detachment rates of H[sup [minus]]. The laser intensity considered ranges from 1 to 40 GW/cm[sup 2] and the laser frequency covers 0.20--0.42 eV (in the c.m. frame). Finally we perform a simulation of intensity-averaged multiphoton detachment rates by considering the experimental conditions of the laser and H[sup [minus]] beams. The results (without any free parameters) are in good agreement with experimental data, both in absolute magnitude and in the threshold behavior.

• OSTI ID: 7203670
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 50:4; 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
ANIONS
BINDING ENERGY
CHARGED PARTICLES
CORRELATIONS
CROSS SECTIONS
ENERGY
FLUX DENSITY
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
IONIZATION
IONS
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
SCALING LAWS
THRESHOLD ENERGY