Molecular dynamics study of the collision-induced rotational alignment of N-2(+) drifting in helium

The full velocity-angular momentum distribution function for gas-phase N-2(+) drifting in helium is calculated using a molecular dynamics method, and utilized to examine collision-induced rotational alignment in detail. These results are also compared with experimental measurements, most especially those of Anthony [J. Chem. Phys. 112, 10269 (2000)] and those appearing in the preceding article [Anthony , J. Chem. Phys. 114, 6654 (2001)]. Both the calculations and experiments show a number of interesting features including, drift velocities which depend upon rotational state, and quadrupolar alignment parameters which change from negative at high velocities to positive at low velocities. (C) 2001 American Institute of Physics.