Charge transfer, vibrational excitation, and dissociative adsorption in molecule--surface collisions: Classical trajectory theory

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.448645· OSTI ID:5748976

Holloway, S; Gadzuk, J W

The consequences of charge transfer processes occurring when a molecular beam of diatomic molecules is directed upon a solid surface are here considered. In analogy with resonance electron scattering from molecules or harpooning processes in atom--diatom collisions, the incident beam could either be scattered into a highly vibrationally excited molecular state, dissociatively scattered, or dissociatively adsorbed due to formation of temporary negative molecular ions which enable redistribution of the incident translation energy of the beam into intramolecular degrees of freedom. In this work, the exact classical trajectories for the diatomic molecule, including internal vibrational motion, are calculated for motion over model diabatic potential surfaces in which surface hopping due to charge transfer/harpooning is accounted for. Connections between classes of trajectories and topological features of the potential energy surfaces (PES) are illustrated. The model is used to study the average translational to vibrational energy transfer as a function of incident kinetic energy and of PES parameters. Branching ratios between scattered and dissociatively adsorbed molecules are obtained as a function of both incident translational and total energy and the role of the intermediate negative ion resonance in influencing the dynamics of molecular processes at surfaces is illustrated. Comparison with quantum mechanical theories is given in a subsequent paper.

• Research Organization: Liverpool University, Donnan Laboratories, Grove Street, Liverpool L69 3BX, England
• OSTI ID: 5748976
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 82:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ADSORPTION
BEAMS
CHARGE EXCHANGE
COLLISIONS
DISSOCIATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
MOLECULAR BEAMS
MOLECULE COLLISIONS
SORPTION
SURFACES
VIBRATIONAL STATES