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

Abstract

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 Ar(129)Xe and Ar(131)Xe 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 Ω = 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((1)S(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 Ω = 1 symmetry, supporting several tunneling/predissociation resonances located ~200 cm(-1) above the C 1 state.

Rotationally resolved PFI-ZEKE photoelectron spectroscopic study of the low-lying electronic states of ArXe+

“…22,23 Their rovibrational energy level structure has been measured at high resolution by 1 VUV + 1 resonance-enhanced twophoton ionization. 24,25 The e-symmetry levels of the C 1 and D 0 + states are not predissociative and have lifetimes on the order of ∼1 ns or more. The f-symmetry levels of the C 1 state are predissociative and their lifetimes decrease with increasing rotational excitation.…”

“…Downloaded to IP: 129.132.118.157 On: Fri, 11 Nov thus predicted to be dominant, and ion-core changing ionization processes result from electronic autoionization. The D 0 + state possesses a regular rovibronic energy level structure 9,24,25 and is thought to have a dominant 6sσ [A 2 1/2] character with weaker 6pπ [A 1 3/2] and possibly also 6pσ [X 1/2] contributions. Single-photon ionization from the D 0 + state therefore provides efficient direct access to the A 2 1/2 and A 1 3/2 states of ArXe + (see Figure 5 of Ref.…”

“…The C 1 state has a strongly perturbed vibrational structure and can be described as a superposition of dominant 6pσ [A 1 3/2], 6sσ [A 2 1/2] and weaker 6pσ [X 1/2] contributions. 22,25 The irregular vibrational structure of the C 1 state could be accounted for semiquantitatively by a twostate adiabatic coupling model involving the 6pσ [A 1 3/2] and 6sσ [A 2 1/2] states. 25 Single-photon ionization from the C 1 state does not only provide efficient direct access to the A 1 3/2 and A 2 1/2 states but also weaker access to the X 1/2 state of ArXe + (see Figure 5 of Ref.…”

Spin–Orbit Coupling and Potential Energy Functions of Ar2+ and Kr2+ by High-Resolution Photoelectron Spectroscopy and ab Initio Quantum Chemistry

“…The potential energy functions of the low-lying electronic states of rare-gas dimer ions are also needed to understand the photoionization dynamics of the neutral rare-gas dimers (see, e.g., refs 8 and 9), to model the electronically excited (Rydberg) states of Rg 2 10 and the structure and fragmentation dynamics of larger rare-gas cluster ions. 11 −13 In past decades, a considerable body of information on the low-lying electronic states of Rg 2 + has been obtained from electronic-structure calculations (see, in particular, refs 14−30); from experiments, primarily photoelectron, photoionization, and electron impact ionization spectroscopy 31−53 (including measurements of photofragment kinetic energy distributions 8,9,54 ); and from a combination of experiment and theory.…”

Rovibrational structure and potential energy function of the ground electronic state of ArXe

“…The hot bands are of particular significance for the study of the X 0 þ ground state of ArXe, because their analysis permits the extraction of information not available from earlier studies. Perturbations in the structure of the C state [25,26] made the C X transitions unsuitable for the analysis of the rovibrational structure of the X 0 þ ground state, and for this reason we chose to use only the D 0 þ ðv 0 ¼ 0 À 3Þ X 0 þ ðv 00 ¼ 0; 1Þ transitions. In order to observe spectra of the very weak hot bands seen in Fig.…”