Radiative charge-transfer lifetime of the excited state of (NaCa){sup +}

Journal Article · Tue Apr 01 04:00:00 EST 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.67.042705· OSTI ID:20633978

Makarov, Oleg P; Cote, R; Michels, H; Smith, W W ^[1]

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1. Department of Physics, University of Connecticut, Storrs, Connecticut 06269-3046 (United States)

New experiments were proposed recently to investigate the regime of cold atomic and molecular ion-atom collision processes in a special hybrid neutral-atom-ion trap under high-vacuum conditions. We study the collisional cooling of laser precooled Ca{sup +} ions by ultracold Na atoms. Modeling this process requires knowledge of the radiative lifetime of the excited singlet A {sup 1}{sigma}{sup +} state of the (NaCa){sup +} molecular system. We calculate the rate coefficient for radiative charge transfer using a semiclassical approach. The dipole radial matrix elements between the ground and the excited states, and the potential curves were calculated using complete active space self-consistent field and Moeller-Plesset second-order perturbation theory with an extended Gaussian basis, 6-311+G (3df). The semiclassical charge-transfer rate coefficient was averaged over a thermal Maxwellian distribution. In addition, we also present elastic collision cross sections and the spin-exchange cross section. The rate coefficient for charge transfer was found to be 2.3x10{sup -16} cm{sup 3}/sec, while those for the elastic and spin-exchange cross sections were found to be several orders of magnitude higher (1.1x10{sup -8} cm{sup 3}/sec and 2.3x10{sup -9} cm{sup 3}/sec, respectively). This confirms our assumption that the milli-Kelvin regime of collisional cooling of calcium ions by sodium atoms is favorable with the respect to low loss of calcium ions due to the charge transfer.

• OSTI ID: 20633978
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 67; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ALGEBRA
ATOM COLLISIONS
ATOMS
CALCIUM COMPOUNDS
CALCIUM IONS
CROSS SECTIONS
DIPOLES
DISTRIBUTION
EXCITED STATES
LIFETIME
MATRIX ELEMENTS
MOLECULAR IONS
PERTURBATION THEORY
RADIATION PRESSURE
SELF-CONSISTENT FIELD
SEMICLASSICAL APPROXIMATION
SIMULATION
SODIUM
SODIUM COMPOUNDS
SPIN EXCHANGE
TRAPS