Production of cold CN molecules by photodissociating ICN precursors in brute-force field

Abstract

We theoretically investigate the production of cold CN molecules by photodissociating ICN precursors in a brute-force field. The energy shifts and adiabatic orientation of the rotational ICN precursors are first investigated as a function of the external field strength. The dynamical photofragmentation of ICN precursors is numerically simulated for cases with and without orienting field. The CN products are compared in terms of their velocity distributions. A small portion of the CN fragments are recoiled to near zero speed in the lab frame by appropriately selecting the photo energy for dissociation. With a precursor ICN molecular beam of ∼ 1.5 K in rotational temperature, the production of low speed CN fragments can be improved by more than 5 times when an orienting electrical field of 100 kV/cm is present. The corresponding production rate for decelerated fragments with speeds ≤ 50 m/s is simulated to be about ∼2.1×10 −4 and CN number densities of 10 8 -10 10 cm −3 can be reached with precursor ICN densities of ∼10 12 -10 14 cm −3 from supersonic expansion.