New analysis of the Douglas – Herzberg system (A1П – X1Σ+) in the CH+ ion radical.

Abstract

Three bands of the A1 ∏ -X1 σ+ system in the 12CH+ ion radical have been rephotographed under high resolution as an emission spectra using a Geissler-type discharge tube. The conventional technique of spectroscopy has been implemented. Using the Th lines as a standards, as well as an interferometric comparator equipped with a photoelectric scanning device, the 0-0, 0-1 and 2-1 bands have been reanalyzed. By means of much longer bands (Jmax = 17 in the Q(J) branch of the 0-0 band; Jmax = 16 in the R(J) branch of the 0-1 band; Jmax = 14 in the P(J) and Q(J) branches of the 2-1 band), than have been observed so far, as well as the merged calculations, using another five bands given by Carrington et al. [A. Carrington, D.A. Ramsay, Phys. Scripta 25, 272 (1982)] additionally, more accurate molecular constants for the X 1 σ+ state, the improved reduced band system origin Te = 24118.726 (14) cm-1 as well as for the first time the equilibrium molecular constants with their one standard deviation for the A1 ∏ state in the CH+ molecule have been computed: ωe′ = 1864.402(22), ωex e′ = 115.832(14), ωeye′ = 2.6301(24), Be′ = 11.88677(72), αe′e = 0.9163(18), γe′ = -2.29(12) × 10-2, εe′ = 4.95(20) × 10-3, D e′ = 1.92960(31) × 10-3, β e′= 1.0733(50) × 10-4, δ e′ = -1.312(16) × 10-5, qe′= 4.102(23) × 10-2, αqe′ = -3.14(16) × 10-3, and qDe′= -2.20(14) × 10 -5 cm-1. Only in our research the addition to the zero-point energy Y00′ = -1.9430 cm-1 and Y 00″ = 1.8953 cm-1 have been calculated. The equilibrium bond lengths of re′ = 1.235053(37) Å and re″ = 1.1308843(30) Å for the A1∏ and X1σ+ states, respectively have been computed. Full quantum-mechanics characteristic of the A-X bands system in the 12CH+ molecule, i.e. RKR turning points, the Franck-Condon factors and r-centroids have been obtained. Dissociation energies D e X1σ+ = (38470 ±3503) cm-1 and De A1∏ = (14415 ±3509) cm-1 for the molecule under consideration have been estimated.