Quenching of H{sub 2} Vibrations in Ultracold {sup 3}He and {sup 4}He Collisions

Journal Article · Wed Apr 01 04:00:00 EST 1998 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.80.3224· OSTI ID:601012

Balakrishnan, N; Forrey, R C; Dalgarno, A ^[1]

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1. Institute for Theoretical Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)

We present results of quantum mechanical scattering calculations including full rovibrational coupling on the relaxation of vibrationally excited H{sub 2} molecules in collision with ultracold {sup 3}He and {sup 4}He atoms. The exothermic vibrational deactivation cross sections exhibit minima at translational temperatures near 10 K and show an inverse velocity dependence in accordance with Wigner{close_quote}s threshold law in the limit of zero kinetic energy. The corresponding rate coefficients exhibit minima before attaining constant values below 10{sup {minus}3} K. The rate coefficients increase by 3 orders of magnitude when the initial vibrational level of the molecule is raised from v=1 to v=10 . The results suggest that quasibound resonance states of {sup 3}HeH{sub 2} and {sup 4}HeH{sub 2} exist, associated with each excited vibrational state of H{sub 2} , and that both the triatomic species {sup 3}HeH{sub 2} and {sup 4}HeH{sub 2} have one bound vibrational state. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 601012
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 15 Vol. 80; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANGULAR MOMENTUM
BOUND STATE
HELIUM 3
HELIUM 4
HYDROGEN
MOLECULE-MOLECULE COLLISIONS
QUANTUM MECHANICS
QUANTUM NUMBERS
QUENCHING
RELAXATION
ROTATION-VIBRATION MODEL
VELOCITY
VIBRATIONAL STATES