Orientation of CHF3 desorbed and scattered from Ag(111): Measurements using electrostatic focusing

A hexapole focusing field provides a general method for determining the orientation of polar polyatomic molecules. In the first application of this method to surface scattering we find that at 620 K CHF3 is 27% more likely to desorb with the fluorine end of the symmetry axis pointing directly away from the surface than with the opposite orientation. As the temperature is lowered, the desorption anisotropy decreases. Direct scattering gives preferential orientation opposite that of desorption. © 1987 The American Physical Society.