Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

Journal Article · Fri Oct 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.042718· OSTI ID:21450786

Tscherbul, T V; Dalgarno, A ^[1]; Klos, J ^[2]; Zygelman, B ^[3]; Pavlovic, Z ^[4]; Hummon, M T; Lu, H -I; Tsikata, E; Doyle, J M ^[1]

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1. Harvard-Massachusetts Institute of Technology Center for Ultracold Atoms, Cambridge, Massachusetts 02138 (United States)
2. Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 (United States)
3. Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, Nevada 89154 (United States)
4. Institute for Theoretical Atomic, Molecular, and Optical Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)

We report a combined experimental and theoretical study of collision-induced dipolar relaxation in a cold spin-polarized gas of atomic nitrogen (N). We use buffer gas cooling to create trapped samples of {sup 14}N and {sup 15}N atoms with densities (5{+-}2)x10{sup 12} cm{sup -3} and measure their magnetic relaxation rates at milli-Kelvin temperatures. These measurements, together with rigorous quantum scattering calculations based on accurate ab initio interaction potentials for the {sup 7}{Sigma}{sub u}{sup +} electronic state of N{sub 2} demonstrate that dipolar relaxation in N+N collisions occurs at a slow rate of {approx}10{sup -13} cm{sup 3}/s over a wide range of temperatures (1 mK to 1 K) and magnetic fields (10 mT to 2 T). The calculated dipolar relaxation rates are insensitive to small variations of the interaction potential and to the magnitude of the spin-exchange interaction, enabling the accurate calibration of the measured N atom density. We find consistency between the calculated and experimentally determined rates. Our results suggest that N atoms are promising candidates for future experiments on sympathetic cooling of molecules.

• OSTI ID: 21450786
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-ATOM COLLISIONS
ATOMS
CALIBRATION
COLLISIONS
COOLING
DENSITY
ELEMENTS
EXCHANGE INTERACTIONS
GAS COOLING
INTERACTIONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC FIELDS
MOLECULES
NITROGEN
NITROGEN 14
NITROGEN 15
NITROGEN ISOTOPES
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORIENTATION
PHYSICAL PROPERTIES
POTENTIALS
RELAXATION
SCATTERING
SPIN EXCHANGE
SPIN ORIENTATION
STABLE ISOTOPES
TEMPERATURE DEPENDENCE
TRAPPING