Quantum interpretation of fully state-selected rotationally inelastic collision experiments

Abstract

We develop an expression for the cross section corresponding to fully oriented rotationally inelastic atom–diatomic molecule collisions in the general case where both the initial and final axes of quantization are arbitrarily oriented with respect to the initial relative velocity vector. The cross section appears as an inner product of a tensor cross section and various rotation matrix elements. Considerable simplification occurs if one averages over the final orientation of the rotational angular momentum. The thermal averaging appropriate to a beam–gas configuration can be reduced to a one-dimensional integration. A detailed discussion is devoted to the potential use of laser induced fluorescence detection to determine experimentally the orientation dependence of rotationally inelastic collisions.