Ab initio studies on nanoscale friction between fluorinated diamond surfaces: effect of model size and level of theory.

Interactions between two fluorinated diamond surfaces placed in contact with each other were investigated with quantum chemical Hartree-Fock and Møller-Plesset perturbation theory and basis sets def-SV(P), def-TZVP, and 6-31G. Two models, C(6)H(6)F(3)-C(24)H(24)F(12) and C(13)H(16)F(6)-C(22)H(24)F(10), were used to examine how model size and level of theory affect the atomic-scale friction, especially the coefficient of friction. Also of interest was a comparison of the interaction energies of the two models with different stacking configurations. The averages of the calculated friction coefficients fell within the range of values 0.28-0.43.