Premium
Dissociative adsorption and associative desorption of H 2 on a flat surface
Author(s) -
Mowrey R. C.,
Dunlap B. I.
Publication year - 1991
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560400857
Subject(s) - potential energy surface , wave function , chebyshev polynomials , chemistry , potential energy , fourier transform , desorption , surface (topology) , quantum , kinetic energy , function (biology) , translation (biology) , molecule , adsorption , molecular physics , physics , atomic physics , quantum mechanics , mathematical analysis , mathematics , geometry , biochemistry , evolutionary biology , messenger rna , gene , biology
Abstract A quantum mechanical time‐dependent method was used to study the dynamics of dissociative adsorption and associative desorption of H 2 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.