[1
]Institut für Physikalische
Chemie, Westfälische Wilhelms-Universität Münster, Corrensstr.
30, D-48149 Münster,
Germany
[2
]Instituto de Física
de
São Carlos, Universidade de São Paulo (USP), C.P. 369, CEP
13560-970, São Carlos, SP, Brazil
[3
]Department of Materials Science
and Engineering, Iowa State University of Science
& Technology, 2200 Hoover Hall, Ames, Iowa 50010, United
States