HIGH-RESOLUTION SPECTROSCOPY OF THE CS2-D 1-SIGMA-U+-X 1-SIGMA-G+ TRANSITION AND HYPERFINE-STRUCTURE

The Doppler-free high resolution laser spectroscopy of Cs2 D1SIGMA(u)+-X1SIGMA(g)+ transition is extended up to v' = 65. By comparing the spectral linewidth and the time-resolved fluorescence intensity, the line broadening observed for transitions to the D1SIGMA(u)+(v' = 63,J' less-than-or-equal-to 70) levels is identified as the lifetime broadening originating from the predissociation. Line splittings are observed for the D 1SIGMA(u)+(v' = 46,J' greater-than-or-equal-to 95)-X1SIGMA(g)+(v'' = 1,J'') transitions and are identified as the hyperfine splitting due to a magnetic dipole interaction between nuclear spin and electron. The hyperfine splitting is attributed to mixing of the (2) 3PI(u) state, whose wave function changes from Hund's case (a) to case (b) at large J. The dependence of the electric dipole transition moment on the internuclear distance for the D1SIGMA(u)+-X1SIGMA(g)+ transition is determined by comparing the observed and calculated line intensities of the dispersed fluorescence.