Structure and dynamics within monolayer films of phenylene oligomer molecules adsorbed onto graphite
Abstract
The structure and dynamics of the aromatic molecules o-terphenyl (o-3P), p-terphenyl (p-3P) and p-quaterphenyl (p-4P) within monolayer films adsorbed onto the surface of graphite has been investigated using elastic and quasielastic neutron scattering. Structural results indicate an orientation consistent with the long molecular axis parallel to the graphite surface. Initial dynamic results indicate a phase change within both p-3P and p-4P films at approximately 300-325 K. At temperatures below this range, the scattering is consistent with reorientation of the phenyl rings around the long molecular axis. At temperatures above 300 K, the scattering is much stronger and appears at lower momentum transfers, indicating some form of translational motion in combination with reorientation of the phenyl rings. The o-3P molecules exhibit motions consistent with both reorientations of the phenyl rings as well as translations at temperatures as low as 190 K. There is no abrupt change in the character of the dynamics for the o-3P films.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARA33013K