OP-II-3

OP-I-6energies of reactants and products corresponding to the Fermi energy of electrons ina metalUg2ad i f i f += 1/ 2[ U + U − ( U −U) 4V](4)where V is an empirical function providing a smooth transition from the region of theinitial potential well to the region of the final one. Two sets of coordinates, thegeometris of the adsorbed molecule(s) and the rearranged surface geometry areintroduced to describe most significant changes as reactants adsorbed transfer intoproducts. We review the main ideas of this approach.Using the kinetic information (Fig. 1) for 5 metals (Pt, Pd, Ir, Rh, Ru) we draw andcompare the bistability domain for either atmospheric pressure or for high-vacuumconditions. The obtained results are compared with available experimental results.We also show its asymptotic limits: the rate constant (k 3 ) is sufficiently large as not toaffect the rate. We also present initial results of a similar approach for predictingoscillatory behavior from first principles.2Fig. 1. Temperature dependence of the rate constants calculated from basic principlesfor Pt (left, k 1 for 1mbar, k 2M for 1 bar) and the predicted hysteresis rate curve at 550Kfor Pd(right, P O2 =1bar).References[1]. E. D. German, A. M. Kuznetsov, M. Sheintuch, Surf. Sci. 2004, 554, 159, 170.[2]. E. D. German, A. M. Kuznetsov, M. Sheintuch, Chem. Phys. 2006, 324, 129.[3]. E. D. German, M. Sheintuch, J. Phys. Chem., C 2007, 111, 9184.[4]. E. D. German, M. Sheintuch, A. M. Kuznetsov, J. Phys. Chem., C 2008, 112, 15510.48