INVESTIGATION OF THE ENERGETICS OF THE DECOMPOSITION OF AZOMETHANE ON Pd(111): THE UBI–QEP APPROACH

Abstract

The method of unity bond index–quadratic exponential potential (UBI–QEP) is employed to derive the energetic parameters associated with the steps of the pathway which we propose for the catalytic decomposition of azomethane on the Pd (111) surface. According to the energy calculations, azomethane adsorbs molecularly in trans-configuration and then decomposes to CH 3 N with no activation energy. The reaction continues by tilting and dehydrogenation to the products ( H 2 and HCN). The calculated activation energies at various surface coverages perfectly account for the variation of relative yields of H 2 and HCN with changing of the coverage of azomethane. According to the calculations, desorption of molecular azomethane at high surface coverage occurs, which is in excellent agreement with experimental data.