title: The K2 2(3)Pi(g) state: new observations and analysis.
abstract: Totally 3045 transitions into the 2(3)Pi(g) v = 0-42, J = 0-103, Omega = 0, 1, 2 rovibrational levels have been observed by infrared-infrared double resonance fluorescence excitation and two-photon spectroscopy. Molecular constants including the spin-orbit interaction parameters are obtained. Although the K2 2(3)Pi(g) state dissociates to the 4s + 3d atomic limit, it is strongly mixed with the 3P ionic states in the range of the potential well. This mixing results in a relatively large equilibrium internuclear distance Re = 5.254 A and a larger spin-orbit constant A0 approximately 14.17 cm(-1) than that of the atomic limit -2.33 cm(-1). Strong perturbations of the 2(3)Pi(g) levels observed are attributed to the spin-orbit coupling with the 4(1)Sigma(g)+ state.
authors.affiliation: Department of Physics and Key Laboratory of Atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084, China.
authors.forename: F
authors.initials: F
authors.lastname: Xie
authors.forename: D
authors.initials: D
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Chu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Magnier
authors.forename: V B
authors.initials: VB
authors.lastname: Sovkov
authors.forename: V S
authors.initials: VS
authors.lastname: Ivanov