Zeeman relaxation of cold atomic iron and nickel in collisions with {sup 3}He

Journal Article · Tue Jun 15 00:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.062706· OSTI ID:21437897

Johnson, Cort; Newman, Bonna; Kleppner, Daniel; Greytak, Thomas J ^[1]; Brahms, Nathan; Doyle, John M ^[2]

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1. Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2. Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

We have measured the ratio {gamma} of the diffusion cross section to the angular momentum reorientation cross section in the colliding Fe-{sup 3}He and Ni-{sup 3}He systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold (<1 K) {sup 3}He buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the {sup 3}He temperature. {gamma} is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine {gamma} accurately, we introduce a model of Zeeman-state dynamics that includes thermal excitations. We find {gamma}{sub Ni-}{sup 3}{sub He}=5x10{sup 3} and {gamma}{sub Fe-}{sup 3}{sub He{<=}}3x10{sup 3} at 0.75 K in a 0.8-T magnetic field. These measurements are interpreted in the context of submerged shell suppression of spin relaxation, as studied previously in transition metals and rare-earth-metal atoms [C. I. Hancox, S. C. Doret, M. T. Hummon, R. V. Krems, and J. M. Doyle, Phys. Rev. Lett. 94, 013201 (2005); C. I. Hancox, S. C. Doret, M. T. Hummon, L. Luo, and J. M. Doyle, Nature (London) 431, 281 (2004); A. Buchachenko, G. Chaasiski, and M. Szczniak, Eur. Phys. J. D 45, 147 (2007)].

• OSTI ID: 21437897
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 81; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR MOMENTUM
ATOM COLLISIONS
ATOMS
COLLISIONS
CROSS SECTIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY-LEVEL TRANSITIONS
EVEN-ODD NUCLEI
EXCITATION
HELIUM 3
HELIUM ISOTOPES
IRON
ISOTOPES
LASER RADIATION
LIGHT NUCLEI
MAGNETIC FIELDS
METALS
NICKEL
NUCLEI
PARTICLE PROPERTIES
RADIATIONS
RARE EARTHS
RELAXATION
SPIN
STABLE ISOTOPES
TRANSITION ELEMENTS
ZEEMAN EFFECT