Spectroscopy of YO from first principles

Abstract

We report an ab initio study on the spectroscopy of the open-shell diatomic molecule yttrium oxide, YO. The study considers the six lowest doublet states, X 2 Σ + , A 2 ∆, A 2 Π, B 2 Σ + , C 2 Π, D 2 Σ + , and a few higher-lying quartet states using high levels of electronic structure theory and accurate nuclear motion calculations. The coupled cluster singles, doubles, and perturbative triples, CCSD(T), and multireference configuration interaction (MRCI) methods are employed in conjunction with a relativistic pseudopotential on the yttrium atom and a series of correlation-consistent basis sets ranging in size from triple-ζ to quintuple-ζ quality. Core-valence correlation effects are taken into account and complete basis set limit extrapolation is performed for CCSD(T). Spin-orbit coupling is included through the use of both MRCI state-interaction with spinorbit (SI-SO) approach and four-component relativistic equationof-motion CCSD calculations. Using the ab initio data for bond lengths ranging from 1.0 to 2.5 Å, we compute 6 potential energy, 12 spin-orbit, 8 electronic angular momentum, 6 electric dipole moment and 12 transition dipole moment (4 parallel and 8 perpendicular) curves which provide a complete description of the spectroscopy of the system of six lowest doublet states. The DUO nuclear motion program is used to solve the coupled nuclear motion Schrödinger equation for these six electronic states. The spectra of 89 Y 16 O simulated for different temperatures are compared with several available high resolution experimental studies; good agreement is found once minor adjustments are made to the electronic excitation energies.

Control direct laser cooling scheme by the optimized electric field

“…The YO 13 molecule with 0.9944 of FCF possesses Res of 1.822 and 1.824 Å for the X 2 Σ + and A 2 Σ + states. 14 Similar results can be found for the previously reported molecules with laser cooling. [15][16][17][18] The laser cooling can also play a role if the cumulative FCF of several transitions reaches high diagonalization, although the FCF of the main transition is not large enough to drive the laser cooling scheme alone.…”

The 2020 release of the ExoMol database: Molecular line lists for exoplanet and other hot atmospheres

“…The CLT line lists for LiH and LiH + due to Coppola et al [164] fall into the few-electron category and should be reliable. The other ab initio line lists provided, namely those for ScH [163] , CH 3 F [167] , AsH 3 [168] , P 2 H 2 [169] , PF 3 [170] , CH 3 [171] and YO [176] must be regarded as intrinsically less accurate than other line lists provided by the database. In the case of YO, work is in progress aimed at producing an empirical line list based on available experimental data.…”

Theoretical rovibronic spectroscopy of the calcium monohydroxide radical (CaOH)

“…Studies in the ExoMol group have shown that rovibronic spectra can be very sensitive to the quality of the underlying PESs and that the "cliff-like" electronic band heads usually emerge after empirical refinement of the excited state PESs. 59 In Fig. 6, the size of the Renner-Teller splitting ΔE RT for the (0, 1 1 , 0) and (0, 2 0 , 0) vibrational states is plotted up to J = 30.5.…”