Four-photon excitation of autoionizing states of Ar, Kr, and Xe between the 2P3/2 and 2P1/2 ionic limits.

Abstract

In a previous paper [Phys. Rev. A 49, 3322 (1994)] we reported on a three-photon excitation study of [ital odd] (in [ital j][sub [ital c]][ital l] coupling notation [ital nl][prime][[ital K]][sub [ital J]], in which the angular momentum of the ion core [ital j][sub [ital c]] is coupled to the orbital momentum of the Rydberg electron [ital l] to give [ital K], which is then coupled to the electron spin to give [ital J]) [ital ns][prime][1/2][sub 1], [ital nd][prime][3/2][sub 1], [ital nd][prime][5/2][sub 3], and [ital ng][prime][7/2][sub 3] autoionizing series of atomic argon, krypton, and xenon. Here, four-photon excitation of [ital even] autoionizing Rydberg states of these rare gases between the [sup 2][ital P][sub 3/2] and [sup 2][ital P][sub 1/2] ionic limits has been investigated using multiphoton ionization and supersonic expansion techniques. In all atoms the [ital np][prime][1/2][sub 0], [ital np][prime][3/2][sub 2], nf[prime][5/2][sub 2], and [ital nf][prime][7/2][sub 4] autoionizing series have been observed. Such states have never been observed before in argon, while in krypton and xenon our experimental conditions have enabled a considerably more accurate and extended investigation than previously possible. The analysis of the resonance line shapes and intensities has allowed for a detailed investigation of the four-photon ionizationmore » dynamics, in particular with respect to the role of the three-photon virtual level.« less