## Abstract

In this paper we present results of coupled channel quantum scattering calculations of the alignment selected j = 3/2 → j = 1/2 fine structure changing integral cross section for Na(^{2}P) + He. This cross section has in the past been written in terms of a coherent sum of partial wave amplitudes, but we have found that it can be expressed in terms of an incoherent sum of partial cross sections, each labeled by the total angular momentum J and by parity. It is also possible to define an alignment selected wave function for each J such that the azimuthal average of the square of this wave function projected onto each final state is proportional to the magnitude of the partial cross section into that state. This J labeled wave function is thus clearly related to the physical measurables, and we have used it to determine propensities for preservation of asymptotically prepared alignment during collisions. Using a potential surface based on Pascale's ab initio calculations, we find that the alignment ratio σ_{⊥}/σ _{∥} is an increasing function of energy, with a value less than unity at low energy (

Original language | English |
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Pages (from-to) | 6961-6972 |

Number of pages | 12 |

Journal | Journal of Chemical Physics |

Volume | 91 |

Issue number | 11 |

Publication status | Published - 1989 |

## ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics