Mobilities of NO+ drifting in helium: A molecular dynamics study

A new molecular dynamics (MD) method is introduced, and used to study NO+ ions drifting in helium under the influence of a uniform electric field. Mobilities, average values of squared velocities, and self-diffusion coefficients parallel and perpendicular to the electric field are reported for two recent ab initio potential surfaces: a coupled cluster singles-doubles with perturbative treatment of triple excitations [CCSD(T)] surface [S. K. Pogrebnya et al., Int. J. Mass Spectrom. Ion Processes 149/150, 207 (1995)] and a MP4SDTQ/6-311 + G(2df, p) surface [L. A. Viehland et al., Chem. Phys. 211, 1 (1996)]. Average values of angular momentum and alignment parameters are also reported and compared. In all cases, no significant differences were found in the calculated values for the two different potential surfaces. Finally, mobility values are compared with experimental measurements [J. A. de Gouw et al., J. Chem. Phys. 105, 10398 (1996)] and good agreement is obtained for both potential surfaces. (C) 1999 American Institute of Physics. [S0021-9606(99)51623-1].