Cold beam of 7 Li 4 He dimers

We demonstrate an approach for producing a high-flux beam of 7 Li 4 He dimers by performing postnozzle seeding of a lithium beam into a supersonic helium expansion. The molecular beam has a longitudinal temperature of 13(6) mK and a continuous flux on the order of 1011 11 dimers/s / s confined within a solid angle of 0.16 sr. Monte Carlo simulations of molecular formation based on ab initio quantum scattering calculations are carried out and compared to the experimentally observed molecular flux. Extensions of this work could lead towards a more quantitative understanding of few-body collision processes of alkali and helium atoms.