Temperature dependence of He(2 [sup 3][ital P][sub [ital J]]) reactions: Collision-induced mixing and conversion to He[sub 2]( [sup 3][Pi][sub g]) molecules

Journal Article · Tue Nov 30 23:00:00 EST 1993 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.48.4350· OSTI ID:5798343

Zhao, X; Soletsky, P A; Bryan, W H; Dunning, F B; Walters, G K ^[1]

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1. Department of Physics and the Rice Quantum Institute, Rice University, P.O. Box 1897, Houston, Texas 77251 (United States)

The rate coefficients for mixing between He(2 [sup 3][ital P][sub [ital J],][ital M[ital J]]) levels during collisions with ground-state helium atoms and for conversion of He(2 [sup 3][ital P][sub [ital J]]) atoms to He[sub 2]([ital b] [sup 3][Pi][sub [ital g]]) molecules via three-body reactions in helium gas have been investigated over the temperature range 1.6--300 K. The measured rate coefficients for collisionally induced [ital P]-state mixing decrease slowly with decreasing temperature, from (1.8[plus minus]0.5)[times]10[sup [minus]9] cm[sup 3] s[sup [minus]1] at 300 K to (4.5[plus minus]0.5)[times]10[sup [minus]10] cm[sup 3] s[sup [minus]1] at 4.2 K. The rate coefficients for the production of He[sub 2]([ital b] [sup 3][Pi][sub [ital g]]) molecules via three-body reactions are observed to increase with decreasing temperature and are described by the relation [ital k][sub [ital P]][congruent](2.5+267[ital T][sup [minus]1])[times]10[sup [minus]32] cm[sup 6] s[sup [minus]1]. This behavior, which is very different from that noted in earlier studies of the conversion of He(2 [sup 3][ital S][sub 1]) atoms to He[sub 2]([ital a] [sup 3][Sigma][sub [ital u]][sup +]) molecules through three-body reactions, suggests that the reaction is not thermally activated.

• OSTI ID: 5798343
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 48:6; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-ATOM COLLISIONS
COLLISIONS
CONVERSION
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
HELIUM
MANY-BODY PROBLEM
MIXING
MOLECULES
NONMETALS
RARE GASES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
THREE-BODY PROBLEM