Sticking Lifetime of Ultracold CaF Molecules in Triplet Interactions

Abstract

A six-dimensional potential energy surface is constructed for the spinpolarized triplet state of CaF−CaF by ab initio calculations at the CCSD(T) level of theory, followed by Gaussian process interpolation. The potential is utilized to calculate the density of states for this bialkaline-earth-halogen system where we find the value 0.038 μK −1 , implying a mean resonance spacing of 26 μK in the collision complex. This value implies an associated Rice−Ramsperger−Kassel−Marcus lifetime of 1.8 μs, thus predicting long-lived complexes in collisions at ultracold temperatures.

Cold Chemistry

“…The surface yields reasonable agreement with the initial rate at which colliding molecules are stuck in the complex but estimates a complex lifetime, 19 μs, that still falls 2 orders of magnitude short of the lifetime estimated in the Hong Kong experiment. The contribution of Sardar and Bohn also computes a six-dimensional PES, in this case the triplet PES for CaF + CaF ultracold collisions . Here, the RRKM lifetime is estimated to be 2 μs.…”