Vibronic analyses of the mass-resolved NeXe spectra near Xe*(6p)

Abstract

New mass-resolved two-photon spectra of NeXe involving molecular Rydberg states that dissociate to Ne+Xe*(6p) have been recorded using the combined techniques of (2+1) resonance enhanced multiphoton ionization and time-of-flight mass spectrometry. Excited state symmetries were deduced from separate spectra recorded with linearly and circularly polarized light. Vibronic analyses show that most of the excited states in this spectral region are essentially repulsive except for shallow minima whose electronic origins lie above their asymptotic dissociation limits. The magnitude of the potential humps for the excited states have been estimated. These results are rationalized in terms of an excited state bonding scheme that is dominated predominately by the interplay between repulsive exchange interactions and attractive long-range forces.

Toward a global and causal understanding of the unusual Rydberg state potential energy curves of the heteronuclear rare gas dimers

“…An extreme case is found for NeXe, where, almost without exception, the Rydberg potential energy curves are repulsive except for shallow minima and humps which lie at energies higher than their asymptotic dissociation limits. 3 The NeXe* potential minima are found to lie Ϸ15 cm Ϫ1 to 130 cm Ϫ1 above their respective asymptotic limits, while the barrier heights have been estimated to be Ϸ15 cm Ϫ1 to 200 cm Ϫ1 . In comparison, the ground state binding energy of NeXe ϩ is Ϸ345 cm Ϫ1 .…”