Li/Li2 supersonic nozzle beam

The characterization of a lithium supersonic nozzle beam has been made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 Torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li2 can be described by a Boltzmann distribution with T v = (195±30) K. The rotational temperature is found to be T r = (70±20) K by band shape analysis. Measurements by quadrupole mass spectrometer indicate that ∼10‐mol. % Li2 dimers are present far downstream for an oven body temperature of 1370 K in the supersonic nozzle expansion. This measured mole fraction is in agreement with the existing dimerization theory.