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

Abstract

We describe two-photon photoassociation (PA) experiments operated in an ultracold gas of metastable ${}^4$He${}^{\ast }$ atoms in the $2^3{S}_1$ 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 ${}^5{\Sigma }_g^{+}$ 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 term of processes limiting the lifetime $\tau$ of the exotic molecule. A value of $\tau =1.4\pm 0.3\mu$s is found, which is discussed in view of two recent calculations of the Penning ionization rate induced by spin-dipole coupling and of the atom-molecule inelastic collisions.

References in corpus (6)

• Bose-Einstein Condensation of Metastable Helium
• Atom-molecule dark states in a Bose-Einstein condensate
• Accurate determination of the scattering length of metastable Helium atoms using dark resonances between atoms and exotic molecules
• Giant Helium Dimers Produced by Photoassociation of Ultracold Metastable Atoms
• Prospects for measurement and control of the scattering length of metastable helium using photoassociation techniques
• Spin-dipole induced lifetime of the least-bound quintet sigma state of He(2S)+He(2S)

Cited by in corpus (3)

• Ultra-high Resolution Spectroscopy with atomic or molecular Dark Resonances: Exact steady-state lineshapes and asymptotic profiles in the adiabatic pulsed regime
• Feshbach resonances in 3He*-4He* mixtures
• Subluminal light pulse propagation in a Λ-type atom-molecule coupled system