Spectra of the predissociated 1g state of Xe2 dissociating to

Two-photon resonantly enhanced multiphoton ionization (REMPI)/time-of-flight (TOF) mass spectra of Xe2 in the region of the Xe∗ 5d[1/2]10 ← Xe (1S0) atomic line at 79987.16 cm−1 are presented. A new band system has been identified whose excited state dissociates to Xe1S0) + Xe∗ 5d[1/210. The upper level was assigned 1g symmetry by polarization measurements, in agreement with theoretical predictions. The excited state in question is strongly predissociated since the molecular transition could only be observed with appreciable intensity by monitoring atomic Xe fragments in TOF detection. An excited state vibrational numbering was deduced from measured vibrational isotope shifts, and molecular parameters were calculated. The vibrational constants derived for all Rydberg states dissociating to Xe(1S0) + Xe∗ 5d[1/2]10 can be rationalized by considering their respective Xe2+ ion-cores and possible interactions with nearby electronic states.