Molecular dynamics was used to investigate surface relaxations of the
three titanium dioxide phases (rutile, anatase and brookite). Atoms wi
th small coordination relax much more than bulk like atoms. They under
go vertical as well as lateral relaxations to compensate the missing b
onds at the top layer. The driving force which determines the directio
n of the relaxation seems to be the improvement of local environments
of top layer atoms. (C) 1997 Elsevier Science B.V.