title: Sign reversal of the spin-orbit constant for the C 3Pi(u) state of N2.
abstract: Ab initio calculations are performed at the multireference configuration-interaction level of theory on the diagonal spin-orbit functions for the lowest non-Rydberg states of (3)Pi(u) symmetry in molecular nitrogen. Spin-orbit constants deduced from the ab initio results confirm the recent suggestion, based on new experimental results, that the C (3)Pi(u) state of N(2), long known to be regular in the region of its potential-energy curve minimum, becomes inverted at higher energies. By removing the effects of the crossing C(') (3)Pi(u) state, it is shown that A(v) for the C state changes sign from positive to negative near v=8, corresponding to a change in principal molecular-orbital configuration from (1sigma(g))(2)(1sigma(u))(2)(2sigma(g))(2)(2sigma(u))(3sigma(g))(2)(1pi(u))(4)(1pi(g)) to (1sigma(g))(2)(1sigma(u))(2)(2sigma(g))(2)(2sigma(u))(2)(3sigma(g))(1pi(u))(3)(1pi(g))(2) at an internuclear distance near 1.4 A.
authors.affiliation: Laboratoire de Modelisation et Simulation Multi Echelle, Universite Paris-Est, MSME FRE 3160 CNRS, 5 Boulevard Descartes, 77454 Marne-La-Vallee, France.
authors.forename: H
authors.initials: H
authors.lastname: Ndome
authors.forename: M
authors.initials: M
authors.lastname: Hochlaf
authors.forename: B R
authors.initials: BR
authors.lastname: Lewis
authors.forename: A N
authors.initials: AN
authors.lastname: Heays
authors.forename: S T
authors.initials: ST
authors.lastname: Gibson
authors.forename: H
authors.initials: H
authors.lastname: Lefebvre-Brion