Observation of the 1 2ΠuXg+ system in Cs2+

Abstract
Predissociation of vibrational levels in the 1 2Πu state of Cs2+ has been observed by monitoring Cs+ photofragments resulting from absorption of laser radiation by the X 2Σg+ ground state. Predissociation of the 1 2Πu state is induced by interaction with the repulsive 1 2Σu+ state and leads to the production of photofragments Cs++Cs in their ground electronic state with center‐of‐mass separation energies around 1 eV. The dominant features of the 1 2ΠuX 2Σg+ band system are confined to the wavelength range between 7700 and 8100 Å. A lower limit for the bond energy of the 1 2Πu state, measured relative to its dissociation limit Cs+(1S0)+Cs(2P1/2) is found to be 0.39±0.1 eV. The spin‐orbit splitting in the 1 2Πu state is measured to be 280 cm1.