ExoMol molecular line lists – XIII. The spectrum of CaO

Abstract

An accurate line list for calcium oxide is presented covering transitions between all bound ro-vibronic levels from the five lowest electronic states3 Π, and b 3 Σ + . The ro-vibronic energies and corresponding wavefunctionts were obtained by solving the fully coupled Schrödinger equation. Ab initio potential energy, spin-orbit, and electronic angular momentum curves were refined by fitting to the experimental frequencies and experimentally derived energies available in the literature. Using our refined model we could (i) reassign the vibronic states for a large portion of the experimentally derived energies [van Groenendael A., Tudorie M., Focsa C., Pinchemel B., Bernath P. F., 2005, J. Mol. Spectrosc., 234, 255], (ii) extended this list of energies to J = 79 − 118 and (iii) suggest a new description of the resonances from the A 1 Σ + -X 1 Σ + system. We used high level ab initio electric dipole moments reported previously [Khalil H., Brites V., Le Quere F., Leonard C., 2011, Chem. Phys., 386, 50] to compute the Einstein A coefficients. Our work is the first fully coupled description of this system. Our line list is the most complete catalogue of spectroscopic transitions available for 40 Ca 16 O and is applicable for temperatures up to at least 5000 K. CaO has yet to be observed astronomically but its transitions are characterised by being particularly strong which should facilitate its detection. The CaO line list is made available in an electronic form as supplementary data to this article and at www.exomol.com.

Spectroscopy of YO from first principles

“…We have decided to apply this rather simplistic procedure because it has marginal effect on the overall accuracy of our model and is sufficient for the goal of this pure ab initio study, not aiming at spectroscopic accuracy. A proper diabatic representation of the YO electronic states will be, however, important when refining the ab initio curves by fitting to experiment, 93 which is a goal of future work. In this study we work directly with the ab initio data in the grid representation without representing ab initio curves analytically.…”

Reaction Kinetics of CaOH with H and O2 and O2CaOH with O: Implications for the Atmospheric Chemistry of Meteoric Calcium

“…The blue emission around the ablation target shows that Ca-bearing species are vaporized in highly excited states. The low-lying excited states Ca( 3 P° J , 3 D J , 1 D 2 ) 24 and CaO( A 1 Σ + , b 3 Σ + , a 3 Π, A ′ 1 Π) 31 have sufficient energy to form CaOH from these reactions. Some of these states are also optically metastable, which increases the probability of reaction.…”

ExoMol line lists – XVIII. The high-temperature spectrum of VO

“…Duo has previously been used to model three electronic states for AlO by Patrascu et al (2014), who computed a line list using this model (Patrascu et al 2015). Lodi et al (2015) consider six coupled electronic states in their study on ScH and Yurchenko et al (2016a) constructed a line list for CaO using 5 electronic states. This is the first example where such a large number (13) of states have been considered.…”