Long-range dispersion C₆ coefficient for SF₆ dimer: Experimental and theoretical study

The long-range dispersion C₆ coefficient for the SF₆ dimer is experimentally measured using a technique that uses the expansion of a supersonic pulse jet into a vacuum. A dynamic model of the jet enables us to correlate the position of the maximal peak in the time-of-flight spectrum with the initial conditions of the experiment and the parameters of the intermolecular interaction potential. Due to the low temperature of the jet target, the C₆ coefficient can be extracted directly from the experimental results. Theoretical calculation of the C₆ dispersion coefficient is also performed by using linearly approximated explicitly correlated coupled-cluster singles and doubles (CCSD(F12)) method with the subsequent utilization of the Casimir-Polder formula. Good agreement of experimental and theoretical results confirms the reliability of results.