Hydrogen adsorption on Pd(133) surface

In this study used is an approach based on measurements of the total energy distribution (TED) of field emitted electrons in order to examine the properties of Pd (133) from the aspect of both hydrogen adsorption and surface hydrides formation. The most favourable sites offered to a hydrogen atom to be adsorbed have been indicated and an attempt to describe the peaks of the enhancement factor R spectrum to the specific adsorption sites has also been made.Comment: to be submitted to the Centr. Eur. J. Phy

Experimental and theoretical studies of the quenching of Li (3p,4p) by N2

International audienceQuenching mechanisms of the Li͑(3p) and Li͑(4p) states in collision with the nitrogen molecule are studied by laser-induced fluorescence spectroscopy and by a quantum chemical calculation. The Li͑(3p) state is observed to be efficiently quenched to the Li͑(3s) state detected as intense 3s → 2p emission. The Li͑(4p) state is efficiently quenched to the Li͑(4s) and Li͑(3d) states detected as 4s-2p and 3d-2p emissions, respectively. The potential-energy surfaces for the Li͑(2s-4p)N2 states show a large number of conical intersections and avoided crossings resulting from the couplings between the ionic (Li^+ N2^−) and covalent configurations. There are a large number of stable excited states, and we give here the spectroscopic constants for the lowest two stable isomers correlating to Li͑(2p)+N2

Ab initio

Ab initio investigation based on density functional theory is performed to determine the behavior of H atom diffusion in Pd(110) surface to the first and second subsurface layers. Potential energy surface is constructed to determine the local minima and activation barriers of H pathways. Contribution of the relaxation of surface atoms in the binding energies of H and activation barriers along the diffusion paths, as well as the zero point energy corrections are also included in this work. The binding energies of H in the second subsurface layer are lower compared to its binding energies in the first subsurface layer and this is attributed to the interaction of H with the surface atoms and the differences in interlayer spacing of the surface layers. Comments on the adsorbate induced Pd(110) (1 × 2) missing/adding-row reconstruction phenomenon is also given with reference to the observed results in this work as H is absorbed from the surface to the first subsurface layer. © 2012 The Physical Society of Japan