HIGH-RESOLUTION LASER SPECTROSCOPY OF THE CS-2-C-(1)PI(U) STATE - PERTURBATION AND PREDISSOCIATION

High resolution spectra of the C-1 Pi(u)(upsilon',J')-X(1) Sigma(g)(+) (upsilon '',J '') transitions of the CS2 molecule were measured by the technique of Doppler-free optical-optical double resonance polarizati on spectroscopy. A number of C-1 Pi(u)(upsilon greater than or equal t o 13,J) levels were found to be strongly perturbed. Transitions to the perturbing levels were observed, and the energy shifts of e and f lev els of the C-1 Pi(u), state were studied and identified as originating from perturbations between the C-1 Pi(u) and (2)(3) Pi(1u) states. Mo lecular constants of the C-1 Pi(u)(upsilon = 7-18) and (2)(3) Pi(1u)(u psilon = upsilon(0) - upsilon(0) + 6) levels were determined. Line spl ittings were observed for the transitions to the C-1 Pi(u)(upsilon = 1 3 and 14,Jf) levels which were identified as hyperfine splittings orig inating from additional interaction with the state. Remarkable line br oadenings were observed in the transitions to the C-1 Pi(u)(upsilon > 15,Je and f) levels, and were identified as originating from the predi ssociation through the dissociative (2)(3) Sigma(u)(+) state. The repu lsive potential curve of the (2)(3) Sigma(u)(+) State was estimated to cross that of the C-1 Pi(u) state around the outer turning point of t he C-1 Pi(u)(upsilon = 16 or 17) level. (C) 1997 American Institute of Physics.