Theoretical investigation of rotational rainbow structures in X--Na/sub 2/ collisions using CI potential surfaces. I. Rigid-rotor X = He scattering and comparison with state-to-state experiments

Journal Article · Wed Apr 01 04:00:00 EST 1981 · J. Chem. Phys.; (United States)

OSTI ID:6535457

Schinke, R; Mueller, W; Meyer, W; McGuire, P

An accurate CI potential energy surface for He--Na/sub 2/ is determined, which is suitable for rigid-rotor scattering calculations for collision energies below 1 eV. In the calculation of the interaction potential electron correlation effects have been considered for the bond orbital of Na/sub 2/ and the 1s orbital of He together with the dispersion attraction between these orbitals using the method of self-consistent electron pairs (SCEP). A very shallow van der Waals minimum of about 0.1 meV is obtained at large internuclear distances. Rigid-rotor infinite-order-sudden (IOS) calculations have been performed for collision energies of 0.05< or =E< or =0.15 eV using an analytical representation for the potential surface constructed with the 52 original ab initio points. The differential cross sections for rotationally elastic and inelastic transitions exhibit the recently predicted rotational rainbow structures. The comparison with the state-to-state experimental data of Bergmann et al. (J. Chem. Phys. 72, 4777 (1980)) is performed for DE/E distributions at fixed laboratory scattering angles and for angular distributions of single Dj cross sections. The qualitative and quantitative agreements are satisfactory. Small deviations occur only in the classically forbidden Dj or angular region.

• Research Organization: Max-Planck-Institut fuer Stroemungsforschung, D-3400 Goettingen, Federal Republic of Germany
• OSTI ID: 6535457
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 74:7; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular &amp; Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
CONFIGURATION INTERACTION
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DIMERS
ELASTIC SCATTERING
ELEMENTS
ENERGY
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
GASES
HELIUM
METALS
MOLECULE COLLISIONS
NONMETALS
POTENTIAL ENERGY
RARE GASES
ROTATIONAL STATES
SCATTERING
SODIUM