Accession Number:

ADA162357

Title:

A Comparison of Quantum, Classical, and Semiclassical Descriptions of a Model, Collinear, Inelastic Collision of Two Diatomic Molecules.

Descriptive Note:

Memorandum rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Report Date:

1985-12-13

Pagination or Media Count:

47.0

Abstract:

The collinear dynamics of a model diatom-diatom system is investigated. The collision partners are harmonic oscillators for which the masses and force constants are chosen to correspond to those of the nitrogen and oxygen molecules. The interaction between the molecules arises from a Lennard-Jones 6-12 potential acting between the inside atoms in the collinear system. Quantum mechanical close coupled calculations are performed for several collision energies ranging from 1.0 ev to 2.25 ev. The state-to-state transition probabilities which are extracted from these calculations are then used as a benchmark for comparison. Semiclassical calculations are performed within the framework of a classical path approximation. A simple scheme to modify the classical path to reflect energy exchange between the collision coordinate and the internal degrees of freedom is found to improve the results. On the whole, the agreement between the semiclassical and the quantum mechanical results is surprisingly good. The classical trajectory calculations correctly display many of the qualitative features of the collisions but the numerical agreement is not as close. Unexpectedly, the classical results do not appear to be improving as the collision energy is increased. Keywords Molecular scattering Vibrational energy transfer Collision dynamics and Collinear collision.

Subject Categories:

  • Nuclear Physics and Elementary Particle Physics
  • Quantum Theory and Relativity

Distribution Statement:

APPROVED FOR PUBLIC RELEASE