ISSN:
0020-7608
Schlagwort(e):
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
A quantum mechanical time-dependent method was used to study the dynamics of dissociative adsorption and associative desorption of H2 on a flat, static surface. We used a two-dimensional model in which the molecular axis was held parallel to the surface and the diatom internuclear separation and distance above the surface were the dynamic variables. A modified London-Eyring-Polanyi-Sato (LEPS) potential described the molecule-surface interactions. The wave function for the molecule was represented by its values on a spatial grid of points. The wave function was propagated by expanding the time evolution operator in a series of Chebyshev polynomials and using the properties of the Fourier transform to calculate the kinetic energy. The computational requirements of the problem were significantly reduced by using an L-shaped grid which deletes a large number of points where it is known a priori that the wave-function amplitude vanishes. State-to-state transition probabilities were calculated as a function of the initial translational and vibrational energy for potentials with early, late, and intermediate barriers. The location of the barrier has a strong effect on the energy threshold for reaction and on the distribution of energy between vibration and translation in the products.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/qua.560400857
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