%0 Journal Article
%A Rytkönen, K.
%A Akola, J.
%A Manninen, M.
%T Sodium atoms and clusters on graphite: a density functional study
%J Physical review / B
%V 69
%N 20
%@ 1098-0121
%C College Park, Md.
%I APS
%M PreJuSER-41606
%P 205404
%D 2004
%Z Record converted from VDB: 12.11.2012
%X Sodium atoms and clusters (Nless than or equal to5) on graphite (0001) are studied using density functional theory, pseudopotentials and periodic boundary conditions. A single Na atom is observed to bind at a hollow site 2.45 Angstrom above the surface with an adsorption energy of 0.51 eV. The small diffusion barrier of 0.06 eV indicates a flat potential energy surface. Increased Na coverage results in a weak adsorbate-substrate interaction, which is evident in the larger separation from the surface in the cases of Na-3, Na-4, Na-5, and the (2x2) Na overlayer. The binding is weak for Na-2, which has a full valence electron shell. The presence of substrate modifies the structures of Na-3, Na-4, and Na-5 significantly, and both Na-4 and Na-5 are distorted from planarity. The calculated formation energies suggest that clustering of atoms is energetically favorable, and that the open shell clusters (e.g., Na-3 and Na-5) can be more abundant on graphite than in the gas phase. Analysis of the lateral charge density distributions of Na and Na-3 shows a charge transfer of similar to0.5 electrons in both cases.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000222095700067
%R 10.1103/PhysRevB.69.205404
%U https://juser.fz-juelich.de/record/41606