Eur. Phys. J. D 39, 261-269 (2006)
https://doi.org/10.1140/epjd/e2006-00084-4

Detection by two-photon ionization and magnetic trapping of cold Rb₂ triplet state molecules^*

¹ Istituto per i Processi Chimico-Fisici del C.N.R., Via G.Moruzzi 1, 56127 Pisa, Italy
² Physics Department, University of Connecticut, Storrs, CT, 06269, USA
³ Laboratoire Aimé Cotton, CNRS, Campus d'Orsay, 91405 Orsay Cedex, France

Corresponding author: ^a olivier.dulieu@lac.u-psud.fr

Received: 29 September 2005
Revised: 24 January 2006
Published online: 20 April 2006

Abstract

We present detailed experimental spectra and accurate theoretical interpretation of resonance-enhanced two-photon ionization of ultracold rubidium molecules in the 14000–17000 cm^-1 transition energy range. The dimers are formed in a magneto-optical trap by photoassociation followed by radiative decay into the a ³Σ_u⁺ lowest triplet state. The theoretical treatment of the process, which reproduces the main features of the spectra, takes into account the photoassociation and decay steps as well as the resonant ionization through the manifold of intermediate gerade states correlated to the 5S + 4D limit. In particular, the energy of the v=1 level of the potential well has been determined for the first time. In addition, a tight constraint has been put on the position of the a ³Σ_u⁺ repulsive wall. Finally, magnetic trapping of rubidium molecules in the a ³Σ_u⁺ state is demonstrated.