title: Adiabatic interaction leading to the avoided crossing between the twin 3(1)Delta(g) and 4(1)Delta(g) Rydberg States in Na2.
abstract: We present detailed investigations of our previously reported observations of the 3(1)Delta(g) and 4(1)Delta(g) Rydberg states having separated-atom limits of Na(3s) + Na(4d) and Na(3s) + Na(4f), respectively, of Na(2) using high-resolution cw optical-optical double resonance spectroscopic measurements and analyzing the assigned rovibrational energy levels both by the individual linear fit method and the Dunham polynomial fit method. We have sorted out e/f-parity observed energy levels, and then from the Dunham polynomial fits of the e-parity levels, we have derived molecular constants and constructed Rydberg-Klein-Rees potentials of the 3(1)Delta(g) and 4(1)Delta(g) states, which appear to be twin states with an avoided crossing at R(c) = 4.10 A and a splitting of DeltaE(c) = 94 cm(-1). The potentials are in good agreement with the ab initio calculations and linear fit results. The Lambda-doubling splittings and the (f-d) l-mixing are investigated. A detailed discussion is focused on the adiabatic interaction of the perturbed molecular wave functions/states causing mutual amplitude/intensity sharing giving rise to avoided crossing between the 3(1)Delta(g) and 4(1)Delta(g) states.
authors.affiliation: Department of Chemistry, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Thou-Jen
authors.initials: TJ
authors.lastname: Whang
authors.forename: Chanchal
authors.initials: C
authors.lastname: Chaudhuri
authors.forename: Ray-Yuan
authors.initials: RY
authors.lastname: Chang
authors.forename: Wei-Xiang
authors.initials: WX
authors.lastname: Chen
authors.forename: Chin-Chun
authors.initials: CC
authors.lastname: Tsai