Simple analytic form for the velocity-angular-momentum distribution function of drifting linear ions
Abstract
A simple analytic form is presented for the full velocity-angular-momentum distribution function for gas-phase linear ions drifting in an atomic bath gas under a constant external electric field. Predictions of temperatures, drift velocities, and alignment parameters from this form are compared in detail against molecular-dynamics calculations for NO+ drifting in helium. The form is accurate, compact, and based upon a physically motivated expansion. In essence, simple Maxwellian-like functions are generalized by allowing appropriate temperatures to become functions of velocity and rotational angular momentum. Over a wide range of reduced field strengths, including the equilibrium state, this form is able to account accurately for many properties at a microscopic level with only a few adjustable parameters.
- Publication:
-
Physical Review A
- Pub Date:
- March 2001
- DOI:
- 10.1103/PhysRevA.63.032503
- Bibcode:
- 2001PhRvA..63c2503B
- Keywords:
-
- 33.15.-e;
- 34.10.+x;
- 34.50.-s;
- Properties of molecules;
- General theories and models of atomic and molecular collisions and interactions;
- Scattering of atoms and molecules