PREDISSOCIATION OF THE CS2 C1-PIU-U STATE

By scanning the frequency of a single-mode dye laser crossed to a molecular beam of Cs2, we measured the excitation spectra of the C 1Πu-X1Σg+ !Óâ+ transition by detecting selectively the molecular fluorescence and the emission from the dissociated Cs(62P3/2 ) atoms. Dependence of the predissociation on each vibrational and rotational level C1Πu (v,J) is studied by comparing the intensities of molecular fluorescence and atomic emission. This predissociation is found to depend strongly on the vibrational quantum number u but weakly on the rotational quantum number J, and to occur most strongly around the v = 3 level. The Franck-Condon factors between the RKR potential curve of the C 1Πu state and several repulsive potential curves are calculated, and are compared with the observed predissociation rates. The potential curve of the (2)3Σu+ state, which is expected to be repulsive and to cause the predissociation through the spin-orbit interaction, is estimated to cross the potential curve of the C 1Πu state between the left turning points of v = 1 and v = 0 levels. © 1990 American Institute of Physics.