Rotationally resolved transitions of the 5fπ 3Πg←4sσ a 3Σ+u and 5fσ 3Σ+g←4sσ a 3Σ+u systems of Ar2 have been observed by laser excitation spectroscopy in a pulsed corona discharge. These systems were previously observed at lower resolution [D. J. Kane et al., J. Chem. Phys. 96, 6407 (1992)] with the system tentatively labeled nlλΠg-a and subsequently assigned as 5fπ 3Πg-a on the basis of theoretical considerations [P. Duplàa and F. Spiegelmann, J. Chem. Phys. 105, 1500 (1996)]. Rotational analyses for the (0-0) and (0-1) bands of both systems are presented and the upper states characterized. The (0-2) bands of the 5fπ-a and 5fσ-a transitions are observed also, as are the (0-0) band of 4fδ 3Δg-a 3Σ+uand the (1-0) and (2-0) bands of 5fπ-a, but with rotational structures insufficiently developed to permit analysis. The linewidths of the rotational lines of the above bands are much broader than are the lines of the 7pσ 3Σ+u-a system previously analyzed [C. M. Herring et al., J. Chem. Phys. 101, 4561 (1994)], presumably because of increased lifetime broadening. Several spectral features observed in the 5fπ 3Πg ←4sσ a 3Σ+u band structures that are not apparently compatible with this upper state assignment are discussed.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry