Lifetime of weakly bound dimers of ultracold metastable helium studied by photoassociation

Journal Article · Thu Mar 15 00:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.75.033415· OSTI ID:20982363

Moal, S; Portier, M; Zahzam, N; Leduc, M ^[1]

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1. Ecole Normale Superieure, Laboratoire Kastler Brossel, 24 rue Lhomond, 75231 Paris Cedex 05 (France)

We describe two-photon photoassociation (PA) experiments operated in an ultracold gas of metastable {sup 4}He{sup *} atoms in the 2 {sup 3}S{sub 1} state. Atom-molecule dark resonances as well as Raman signals provide information on the exotic molecule in the least bound vibrational J=2, v=14 state of the {sup 5}{sigma}{sub g}{sup +} interaction potential of two spin-polarized metastable atoms. The physical origin of the various two-photon PA signals is first discussed. Their linewidths are interpreted in terms of processes limiting the lifetime {tau} of the exotic molecule. A value of {tau}=1.4{+-}0.3 {mu}s is found, which significantly differs from two recent calculations of the Penning ionization rate induced by spin-dipole coupling [T. J. Beams et al., Phys. Rev. A 74, 014702 (2006); M. Portier and G. V. Shlyapnikov (unpublished)]. The limitation of {tau} by atom-molecule inelastic collisions is investigated and ruled out.

• OSTI ID: 20982363
• Journal Information: Physical Review. A, Vol. 75, Issue 3; Other Information: DOI: 10.1103/PhysRevA.75.033415; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOM-MOLECULE COLLISIONS
DIMERS
DIPOLES
ELECTRONIC STRUCTURE
HELIUM
HELIUM 4
INELASTIC SCATTERING
LIFETIME
METASTABLE STATES
MOLECULES
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
PHOTON-ATOM COLLISIONS
RAMAN SPECTRA
RESONANCE
SPIN
SPIN ORIENTATION
TEMPERATURE RANGE 0000-0013 K
VIBRATIONAL STATES