Structure and dynamics of the electronically excited C 1 and D 0+ states of ArXe from high-resolution vacuum ultraviolet spectra

Vacuum ultraviolet spectra of the C 1 <-- X 0(+) and D 0(+) <-- X 0(+) band systems of ArXe have been recorded at high resolution. Analysis of the rotational structure of the spectra of several isotopomers, and in the case of (ArXe)-Xe-129 and (ArXe)-Xe-131 also of the hyperfine structure, has led to the derivation of a complete set of spectroscopic parameters for the C 1 and D 0(+) states. The rovibrational energy level structure of the C 1 state reveals strong homogeneous perturbations with neighboring Omega = 1 electronic states. The analysis of isotopic shifts led to a reassignment of the vibrational structure of the C 1 state. The observation of electronically excited Xe fragments following excitation to the C state rotational levels of f parity indicates that the C state is predissociated by the electronic state of 0(-) symmetry associated with the Ar(S-1(0)) + Xe(6s'[1/2](0)(o)) dissociation limit. The observed predissociation dynamics differ both qualitatively and quantitatively from the behavior reported in previous investigations. An adiabatic two-state coupling model has been derived which accounts for the irregularities observed in the rovibronic and hyperfine level structure of the C 1 state. The model predicts the existence of a second state of Omega = 1 symmetry, supporting several tunneling/predissociation resonances located similar to 200 cm(-1) above the C 1 state. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3682770]