Publication No.37



J. Torres, R. Viteri, A. Stashans. A theoretical study
of water adsorption on the SrTiO3 (001) surface considering 
cubic and tetragonal lattices - 20th Europ. Conf. Surf. 
Sci., Krakow (Poland), 2001.

Abstract:
	The importance of SrTiO3 especially due to its catalytic 
properties is well known. In this paper we present a study of water 
molecule adsorption process on a SrTiO3 (001) surface. The calculations 
are carried out using the computational program CLUSTERD. The method 
is based on the Hartree-Fock theory and the so-called LUC (large unit 
cell) model. 
	In the cubic lattice water molecule is adsorbed preferably on 
strontium-oxygen face. The hydrogen atoms form hydrogen bridges with 
two neighbour oxygen atoms (1.2 �) of the surface while the distance 
between water-oxygen atom and closest surface strontium is 1.08 �. The 
geometry of water molecule is affected by the surface, the H-O bond is 
1.2 � and the angle of the molecule is 127�. We observe charge 
redistribution for atoms taking part in the process. In particular, 
surface oxygens become more negative by 0.1 e. 

In the tetragonal lattice water molecule is adsorbed preferably on 
titanium-oxygen face. Only one hydrogen bridge is formed with the 
distance equal to 1.05 �. The geometry of the water molecule changes: 
the O-H bond length is 0.94 � and the molecular angle is 160�. We also 
observe charge redistribution with oxygens tending to become more 
positive. 




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