A variable temperature scanning tunneling microscope was used to directly observe the thermally induced rotation of a single acetylene molecule between two equivalent orientations on Cu(001) above 68 K. Measurements of the rotation rate as a function of temperature yielded an energy barrier of 169±3 meV and a preexponential factor of 1011.8±0.2 s-1. Thermal diffusion of individual acetylene molecules was monitored above 178 K by single molecule tracking. A diffusion barrier of 0.53±0.01 eV and a preexponential factor of 1013.6±0.2 s-1 were determined by measuring the hopping rate as a function of temperature.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry