New analysis of the 12C16O+(B2E+-X2E+) system: Spin-orbit and spin-rotation coupling of the X2E+state

In the present work a new experimental and theoretical analysis of the B2E+ & RARR; X2E+ system of the molecular ion 12C16O+ is performed. New transitions regarding the vibrational levels v ⠄ = 4 of the B2E+ electronic state and the vibrational level v ⠄⠄ = 7 of the electronic state X2E+ have been recorded. For rationalising the experimental observations, molecular structure calculations were carried out and, from them, a detailed investigation about the fine structure of rotational levels of the X2E+ could be per-formed. For such, the spin-rotational constant, y, is characterised through the Ag & BOTTOM; calculation, the per-pendicular component of the electronic g-tensor, in combination with Curl's relation. At equilibrium ge-ometry, the present Ag & BOTTOM; is computed using the multireference configuration interaction wavefunction to be -2430 ppm in agreement with the experimental one [ -2344 ppm]. The R-dependence of the g-tensor has been explored in order to estimate the theoretical yv ( v = 0 -7). In addition, the importance of the lowest 11 states in this kind of calculation is widely discussed. A comparison between experiment and theory is presented, validating our findings and the methodology employed in our analysis.& COPY; 2023 Elsevier Ltd. All rights reserved.