OPTICAL OPTICAL DOUBLE-RESONANCE SPECTROSCOPY OF CL2 - 1ST OBSERVATION AND ANALYSIS OF THE OG-(3P1) ION-PAIR STATE AND THE LOWER-LYING B' 3-PI(0U-) VALENCE STATE

The perturbation facilitated optical-optical double resonance technique allows access to the 0g- (3P1) ion-pair state through the A 3-PI(1u) upsilon = 9 intermediate state where the A 3-PI(1u) approximately B' 3-PI(0u-) interaction occurs: 0g- (3P1)-{A 3-PI(1u) approximately B' 3-PI(0u-)}-X 1-SIGMA-g+. Molecular constants of the 0g- (3P1) state are derived from 197 transitions in the 0 less-than-or-equal-to upsilon' less-than-or-equal-to 15 and 15 and 9 less-than-or-equal-to J' less-than-or-equal-to 47 range, and a Rydberg-Klein-Rees (RKR) potential based on these constants is given. The dispersed fluorescence spectra of the 0g- (3P1)-B' 3-PI(0u-) system are used to establish the absolute vibrational numbering of the 0g- (3P1) state, and also to characterize the new B' 3-PI(0u-) state in view of the Franck-Condon factor consideration.