Münster 1999 – scientific programme
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CP: Chemische Physik
CP 31: Poster: Große Moleküle und Aggregate
CP 31.5: Poster
Monday, March 22, 1999, 18:00–20:00, R52/R72
Ab initio molecular-dynamics simulations of dye molecules on surfaces — •M. Sugihara1, H. Meyer2, P. Entel1, V. Buss3, S. Falzewski3, and J. Hafner4 — 1Theoretische Physik, Universit"at Duisburg, Duisburg — 2MPI f"ur Polymerforschung, Mainz — 3Theoretische Chemie, Universit"at Duisburg, Duisburg — 4Theoretische Physik, TU Wien, Wien
We have performed ab initio total energy calculations and molecular-dynamics simulations of dye molecules in water and on surfaces. With respect to photochemistry the study of the behavior of dye molecules on AgCl or AgBr surfaces would be of interest. Because of the many valence electrons of Ag we have investigated as a preliminary study the behavior of dye molecules on the NaCl(100) surface. We have simulated the flat dye molecule trimethin, [C19H17N2O2]+, which forms sandwich-like structures [1], and the cyanine molecule dimethylmethin, [C21H23N2]+, which shows a typical stereochemical deformation due to two repulsive methyl groups. The molecular-dynamics simulations are able to reproduce the experimentally observed configuration of the charged molecules [2]. The behavior of trimethin, [C7H15N2]+, in water has also been simulated. The calculations are using density functional theory with pseudopotentials and a plane-wave basis set as implemented in the Vienna ab initio simulation package (VASP) [3].
[1] V. Czikkely, H. D. F"orsterling, and H. Kuhn, Chem. Phys. Lett. 6, 11 (1970).
[2] H. Meyer, Y. Sakamoto, and P. Entel, to be published.
[3] G. Kresse and J. Hafner, Phys. Rev. B 49, 14 251 (1994).