Spin relaxation of rubidium atoms in sudden and quasi-molecular collisions with light-noble-gas atoms
Spin relaxation of optically pumped Rb/sup 85/ and Rb/sup 87/ atoms colliding with light-noble-gas atoms is shown to be strongly influenced by an anomalous relaxation process which we attribute to the formation and destruction of bound and quasibound van der Waals molecules. The anomalous relaxation rate has been measured and analyzed in Ne, complementing an earlier study in He. Relative rates of formation of complexes in two- and three-body collisions have been determined. The correlation time for the quasi-molecular interaction in Rb-Ne has been found to be 6.7 x 10/sup -10/p/sup -1/ sec, where p is the Ne pressure in Torr. Nuclear-spin-independent cross sections for the relaxation of < S/sub z/ > in sudden binary collisions of Rb atoms with noble-gas atoms have been measured to be (units of 10/sup -24/ cm/sup 2/): sigma (Rb-He) = 3.1, sigma (Rb-Ne) = 19, sigma (Rb-Ar) = 630, sigma (Rb-N/sub 2/) = 83. Relaxation in sudden binary collisions is shown to follow the theoretically expected nuclear spin dynamics: two relaxation rates in the ratios 8:1 for Rb/sup 87/ and 18:1 for Rb/sup 85/ have been measured. Diffusion coefficients of Rb in the various buffer gases have been measured to be (units of cm/sup 2//sec, at 305 degreeK): D/sub 0/(Rb-He) = 0.42, D/sub 0/(Rb-Ne) = 0.235, D/sub 0/(Rb-Ar) = 0.16, D/sub 0/(Rb-N/sub 2/) = 0.16. Nuclear-spin-independent cross sections for the relaxation of < J/sub z/ > in the 5 /sup 2/P/sub 1///sub 2/ state of Rb have been measured to be 3.4 x 10/sup -16/ cm/sup 2/ for Rb-He, and 5.9 x 10/sup -16/ cm/sup 2/ for Rb-Ne. Anomalies, disagreements, and puzzles occurring in earlier measurements of ground-state relaxation in Rb are shown to be largely resolved when considered in the light of the new results. (AIP)
- Research Organization:
- Department of Physics, Indiana University, Bloomington, Indiana 47401
- OSTI ID:
- 7350745
- Journal Information:
- Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 14:5; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METAL COMPLEXES
ALKALI METAL ISOTOPES
ALKALI METALS
ARGON
ATOM COLLISIONS
ATOM-ATOM COLLISIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COLLISIONS
COMPLEXES
CROSS SECTIONS
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
HELIUM
INTERMEDIATE MASS NUCLEI
ISOTOPES
METALS
NEON
NITROGEN
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
OPTICAL PUMPING
RADIOISOTOPES
RARE GASES
RELAXATION
RUBIDIUM
RUBIDIUM 85
RUBIDIUM 87
RUBIDIUM COMPLEXES
RUBIDIUM ISOTOPES
SPIN-SPIN RELAXATION
STABLE ISOTOPES
THERMAL DIFFUSION
YEARS LIVING RADIOISOTOPES