Cold beam of Li7He4 dimers

We demonstrate an approach for producing a high-flux beam of ${}^7\mathrm{Li}{}^4\mathrm{He}$ 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 ${10}^{11}$ dimers/s confined within a solid angle of 0.16 sr. Monte Carlo simulations of molecular formation based on $\mathit{ab}$ 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.