AUTHOR=Li Donghui , Fayyaz Faiza , Bian Wensheng 

TITLE=A theoretical study on excited-state dynamical properties and laser cooling of zinc monohydride including spin-orbit couplings

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2024.1460224

DOI=10.3389/fchem.2024.1460224

ISSN=2296-2646

ABSTRACT=By means of highly accurate ab initio and dynamical calculations, we identify a suitable laser cooling candidate that contains a transition metal element, namely zinc monohydride (ZnH). The internally contracted multireference configuration interaction method is employed to compute the five lowest-lying Λ-S states of ZnH with the spin-orbit coupling effects included, and very good agreement is obtained between our calculated and experimental spectroscopic data. Our findings show that the position of crossing point of the A 2 Π and B 2 Σ + states of ZnH is above the v′ = 2 vibrational level of the A 2 Π state indicating that the crossings with higher electronic states will have no effect on laser cooling. Hence, we construct a feasible laser-cooling scheme for ZnH using five lasers based on the A 2 Π1/2 → X 2 Σ + 1/2 transition, which features a large vibrational branching ratio R00 (0.8458), a large number of scattered photons (9.8×10 3 ) and an extremely short radiative lifetime (64 ns). The present work demonstrates the importance of electronic state crossings and spin-orbit couplings in the study of molecular laser cooling.