Merging two molecular beams of ND3 up to the Liouville limit

In low-energy collisions between two dipolar molecules, the long-range dipole–dipole interaction plays an important role in the scattering dynamics. Merged beam configurations offer the lowest collision energies achievable, but they generally cannot be applied to most dipole–dipole systems as the electrodes used to merge one beam would deflect the other. This paper covers the design and implementation of a merged electrostatic guide whose geometry was numerically optimized for ND3–ND3 and ND3–NH3 collisions. This device guides both beams simultaneously and makes them converge up to an effective collision angle of 2°, yielding the optimal compromise between spatial overlap and the lowest possible collision energy. We present preliminary data for inelastic ND3–ND3 collisions.