Doppler-free high resolution laser spectroscopy of the Na_2 C~1II_u state: Perturbation and predissociation

摘要

High resolution absorption psectra of the C~1II_u<-x~1SUN_g~+ transition of the ~(23)Na_2 molecule have been measured in the range 29680-30950 cm~(-1) by exploiting the technique of Doppler-free UV-visible optical-optical double resonance polarization spectoscopy. The molecular constants of the C~1II_u (v = 0-10) levels are determined, and the Rydberg-Klein-Rees potential energy curve is calcualted. A number of C~1II_v (v = 0-9, Je and f) levels were found to be perturbed. The energy shifts of e and f parity levels of the C~1II_u state were studied and identified as originating from perturbations between the C~1II_u and 3 ~3SUM_u~+ states. Remarkable line broadenings were observed only in the perturbed region and identified as the lifetime broadening effect originating from indirect (accidental) predissociation throgh the two diabatic ~3Sum_u~+ states.