A pseudopotential hole-particle treatment of neutral rare gas excimer systems. II. The Rydberg states of the Ar*2 dimer

Abstract

A pseudopotential hole-particle model (corresponding to the formalism introduced in paper I) is applied to the determination of the Rydberg states of the Ar2* excimer with and without spin–orbit coupling. All the Λ–Σ Rydberg states (without spin–orbit coupling) adiabatically dissociating into Ar+Ar* (4s,4p,3d,5s,5p,4d), are investigated and all Ω states adiabatically dissociating into Ar+Ar*(4s,4p) have been determined including spin–orbit coupling. The calculation also includes at short distance attractive molecular configurations diabatically correlated with higher atomic asymptotes. The nature of the Λ–Σ states is analyzed and assigned with reference to the Rydberg orbitals of the Kr* united atom limit. Extensive comparison with previous calculations and experiments is carried on. For the lowest ungerade states (1)1u, 0−u, (1)0+u, and (2)0+u, good quantitative agreement is found with experimental high resolution studies. Several members of Rydberg series are calculated and assigned, yielding intra-Rydberg transition energies (1)3Σ+u((1)1u,0−u)→m 3Πg or m 3Σ+g in good correspondence with recent intra-Rydberg spectroscopy experiments. In particular the present calculation provides a likely interpretation of the infrared spectra of Ar2* as due to (1)3Σ+u→(1)3Σ+g transitions with an upper corresponding Ω state (1)1g,0−g containing quasi-bound vibrational levels.