Nonresonant excess photon detachment of negative hydrogen ions

Journal Article · Wed Dec 01 00:00:00 EST 1999 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.60.4753· OSTI ID:20217931

Gulley, M S ^[1]; Zhao, Xin Miao ^[1]; Bryant, H C ^[2]; Strauss, Charlie E. M. ^[1]; Funk, David J ^[1]; Stintz, A ^[2]; Rislove, D C ^[2]; Kyrala, G A ^[1]; Ingalls, W B ^[1]; Miller, W A ^[2]

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1. Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)
2. Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

One-photon detachment and two-photon nonresonant excess photon detachment of electrons from the H{sup -} ion (outer-electron binding energy = 0.7542 eV) are observed with 1.165 eV laser pulses from a Nd:YAG laser (where YAG denotes yttrium aluminum garnet). A Penning ion source produces a pulsed 8 {mu}A, 35 keV H{sup -} beam that intersects a laser beam cylindrically focused down to a 17 {mu}m full width at half maximum waist in the ion beam direction, creating a high-intensity interaction region with peak intensities of up to 10{sup 11} W/cm{sup 2}. The interaction time is 7 ps. The detached electrons are detected by a time-of-flight apparatus enabling us to detect a very small two-photon signal in the presence of a very large signal from single photon detachments. By rotating the linear polarization angle, we study the angular distribution of the electrons for both one- and two-photon detachments. The spectra are modeled to determine the asymmetry parameters and one- and two-photon cross sections. We find {beta}{sub 2} to be 2.54+0.44/-0.60 and {beta}{sub 4} to be 2.29+0.07/-0.31, corresponding to a D state of 89+3/-12% of the S wave and D wave detachments for the two-photon results. The relative phase angle between the S and D amplitudes is measured to be less than 59 degree sign . The measured cross sections are found to be consistent with theoretical predictions. The one-photon photodetachment cross section is measured to be (3.6{+-}1.7)x10{sup -17} cm{sup 2}. The two-photon photodetachment generalized cross section is (1.3{+-}0.5)x10{sup -48} cm{sup 4} sec, consistent with theoretical calculations of the cross section. The three-photon generalized cross section is less than 4.4x10{sup -79} cm{sup 6} sec{sup 2}. (c) 1999 The American Physical Society.

• OSTI ID: 20217931
• Journal Information: Physical Review. A, Vol. 60, Issue 6; Other Information: PBD: Dec 1999; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HYDROGEN IONS 1 MINUS
PHOTON-ATOM COLLISIONS
ELECTRON DETACHMENT
MULTI-PHOTON PROCESSES
EXPERIMENTAL DATA
THEORETICAL DATA