The interaction of platinum single atoms with a pristine vitreous silica substrate was investigated using a molecular dynamics computer simulation technique. The simulation involved a combination of a modified Born-Mayer-Huggins potential and a simple Lennard-Jones (12-6) potential. The parameters used were those established previously for applicability to this system. The Pt adatoms were deposited on substrates held at various temperatures (300-1500 K) as well as on a substrate with artificially immobilized atoms. This allowed a direct evaluation of the thermal accommodation process and its temperature dependence, as well as the overall effect of substrate relaxations on the behavior of the Pt adatoms. The simulations showed rapid thermal accommodation of the Pt adatoms on the 300 K substrates, whereas this effect was lessened considerably on the heated (1500 K) substrates. The inefficient accommodation of the hotter substrate resulted in penetration of the Pt into the subsurface region of the film. In those runs where the substrate atoms were held immobilized, the behavior of the Pt adatoms was significantly different.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces