Ndome, H.Hochlaf, M.Lewis, B. R.Heays, AlanGibson, S. T.Lefebvre-Brion, H.2015-11-232015-11-230021-9606http://hdl.handle.net/1885/16617Ab 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 ³Πᵤ symmetry in molecular nitrogen. Spin-orbit constants deduced from the ab initio results confirm the recent suggestion, based on new experimental results, that the C³Πᵤ state of N₂, 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′ ³Πᵤ state, it is shown that Av for the C state changes sign from positive to negative near v=8, corresponding to a change in principal molecular-orbital configuration from (1σg)²(1σu)²(2σg)²(2σu)(3σg)²(1πu)⁴(1πg) to (1σg)²(1σu)²(2σg)²(2σu)²(3σg)(1πu)³(1πg)² at an internuclear distance near 1.4 Å.This work was supported by the Australian Research Council Discovery Program under Grant Nos. DP0558962 and DP0773050.http://www.sherpa.ac.uk/romeo/issn/0021-9606..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 23/11/15). Copyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in The Journal of Chemical Physics and may be found at https://doi.org/10.1063/1.2990658Keywords: Orbits; Sulfur compounds; Ab initio; Ab initio calculations; Energy curves; Interaction levels; Internuclear distances; Molecular nitrogens; Multireference configurations; Orbital configurations; Sign reversals; Spin dynamics2008-10-2410.1063/1.29906582016-02-24