Experimental versus theoretical rates for photoassociation and for formation of ultracold molecules

We report on the spectra of the long-range attractive molecular states of t he Cs-2 dimer below the dissociation limits 6s + 6p(1/2) and 6s + 6p(3/2) w hich are accessible by molecular photoassociation of cold Cs atoms. For the states 0(u)(+) and 0(g)(-) (6s + 6p(3/2)), we have pei formed trap-loss me asurements, which are in good agreement with the theoretical calculations, performed in a perturbative approach. Far the 0(g)(-) and 1(u) (6s + 6p(3/2 )) states, we observe, after spontaneous decay of the electronically excite d molecules, the formation of translationally cold molecules. A rate of for mation of cold molecules of the order of similar to 10(6) molecules per sec ond is obtained in the case of the state 0(g)(-).