Comparison of quantum, classical, and semiclassical descriptions of a model, collinear, inelastic collision of two diatomic molecules. Memorandum report

Technical Report · Fri Dec 13 04:00:00 EST 1985

OSTI ID:6054904

Page, M; Oran, E S; Boris, J P; Miller, D; Wyatt, R E

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.

• Research Organization: Naval Research Lab., Washington, DC (USA)
• OSTI ID: 6054904
• Report Number(s): AD-A-162357/8/XAB; NRL-MR-5700
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
COLLISIONS
COORDINATES
DYNAMICS
ELEMENTS
ENERGY TRANSFER
INELASTIC SCATTERING
LENNARD-JONES POTENTIAL
MATHEMATICS
MECHANICS
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
MOLECULES
NITROGEN
NONMETALS
NUMERICAL ANALYSIS
OXYGEN
POTENTIALS
PROBABILITY
SCATTERING
TRAJECTORIES