2021/09/08 by Joseph Schnaubelt, Jamie Shaw, Schnaubelt, J. C. +3
Physics and Astronomy · Chemistry · #Cold Atom Physics and Bose-Einstein Condensates #Spectroscopy and Laser Applications #Atomic and Subatomic Physics Research
paper · pdf · doi:10.48550/arxiv.2109.03953
Ultracold CH radicals promise a fruitful testbed for probing quantum-state controllable organic chemistry. In this work, we calculate CH vibrational branching ratios (VBRs) and rotational branching ratios (RBRs) with ground state mixing. We subsequently use these values to inform optical cycling proposals and consider two possible radiative cooling schemes using the X2Π← A2Δ and X2Π← B2Σ- transitions. As a first step towards laser cooled CH, we characterize the effective buffer gas cooling of this species and produce ∼5×1010 CH molecules per pulse with a rotational temperature of 2(1) K and a translational temperature of 7(2) K. We also determine the CH-helium collisional cross section to be 2.4(8)×10-14 cm2. This value is crucial to correctly account for collisional broadening and accurately extract the in-cell CH density. These cold CH molecules mark an ideal starting point for future laser cooling and trapping experiments and tests of cold organic chemistry.