Theoretical studies of molecule surface scattering: Rotationally inelastic diffraction and dissociative dynamics of H[sub 2] on metals

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7206664

Cruz Pol, A J

The interaction of H[sub 2] and its isotopes with metal surfaces has been the subject of many investigations. The scattering experiments provide data such as the final rotational state distribution, sticking coefficients, kinetic energy distribution, and diffraction data. In the first study of this thesis the author implemented a model for looking at the rotationally inelastic diffraction probabilities for H[sub 2], HD, and D[sub 2], as a function of surface temperature. The surface is treated in a quantum mechanical fashion using a recently developed formalism. The center of mass translational motion is treated semiclassically using Gaussian wave packets, and the rotations are described quantum mechanically. The phonon summed rotation-diffraction probabilities as well as the probability distribution for a scattering molecule exchanging an amount of energy [Delta]E with the surface were computed. In the second and third study of this thesis the author implemented a mixed quantum-classical model to compute the probability for dissociation and rotational excitation for H[sub 2], HD, and D[sub 2] scattered from Ni(100) dimensionally in dynamics simulations. Of the six degrees of freedom for the dissociative adsorption of a diatomic molecule on a static surface, the author treats Z,d the center of mass distance above the surface plan, r, the internuclear separation, [theta], the polar orientation angle, quantum mechanically. The remaining three degrees of freedom, X and Y, the center of mass position on the surface plane, and [o], the azimuthal orientation angle, are treated classically. Probabilities for dissociation and ro-vibrational excitation are computed as a function of incident translational energy. Two sudden approximations are tested, in which either the center of mass translation parallel to the surface or the azimuthal orientation of the molecule are frozen. Comparisons are made between low and high dimensionality results and with fully classical results.

• Research Organization: Massachusetts Univ., Amherst, MA (United States)
• OSTI ID: 7206664
• Country of Publication: United States
• Language: English

Related Subjects

664000* -- Atomic & Molecular Physics-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
DEUTERIDES
DEUTERIUM
DEUTERIUM COMPOUNDS
DIFFRACTION MODELS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
HYDROGEN COMPOUNDS
HYDROGEN DEUTERIDE
HYDROGEN ISOTOPES
INELASTIC SCATTERING
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL MODELS
METALS
NUCLEI
ODD-ODD NUCLEI
PARTICLE MODELS
ROTATIONAL STATES
SCATTERING
STABLE ISOTOPES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE