Predissociation induced by ungerade-gerade symmetry breaking in the B (1)Pi(u) state of the (LiLi)-Li-6-Li-7 molecule - art. no. 042507

Unlike the (LiLi)-Li-6-Li-6 and (LiLi)-Li-7-Li-7 isotopomers, the (LiLi)-Li -6-Li-7 molecule exhibits surprisingly high dissociation rates for the leve ls that lie just above the dissociation limit of the B (IIu)-I-1 state. As shown by Cacciani and Kokoouline [Phys. Rev. Lett. 84, 5296 (2000)] they ca n be attributed to a coupling between the B (IIu)-I-1 and 1 (IIg)-I-1 state s, through the breaking of the ungerade-gerade symmetry. Systematic measure ments of these dissociation rates have been performed by discriminating ato mic fluorescence from molecular fluorescence in a sub-Doppler experiment in volving a beam of lithium dimers and a cw tunable laser beam. Calculations of dissociation rates have been performed in the framework of a perturbativ e approach, by solving the coupled Schrodinger equations through the use of the mapped Fourier grid representation method. Measured and calculated dis sociation rates are in excellent agreement for a unique value of the coupli ng strength h = 0.144 cm(-1).