Differentiating Between Hydrogen and Fluorine on a Diamond Surface

We have computed the interaction energies for pyridine (C5H5N) and (CH3)3PO with H and F atoms on the surface of diamond (111) as a function of the type of neighboring surface atom. The pyridine-H and -F interaction energies differ by about 5 kcal/mol, which is only about 1/3 of that found for a one-dimensional model for the surface. The difference in the interaction energies for (CH3)3PO is larger. However, the (CH3)3PO-neighbor interaction energy is larger than for purloiner so that the (CH3)3PO-H interaction becomes repulsive for six neighboring F atoms, Substituting CN for F dramatically increases the repulsion between the surface atoms and molecules. The repulsion is sufficiently large that H/CN does not appear to be better than H/F as a possible way to store data on a surface. While the pyridine shows some potential as a possible probe to differentiate between H and F on a diamond surface, it is not ideal.