Ab initio calculations of the dispersion contribution to the physisorption potential: Application to the N2-BN system.
Résumé
We have developed an ab initio method to calc. the long-range dispersion coeff. for a mol. adsorbing on a surface modeled by a biperiodic slab. The variations of the dynamic polarizabilities vs. imaginary frequencies of each system-considered sep.-permit us to evaluate a C4 dispersion coeff., via the Casimir-Polder formula. The polarizability of the mol. is computed by using the time-dependent gauge-invariant variational method while the elec. properties of the surface are calcd. by using the periodic ab initio LCAO d. functional theory method implemented in the CRYSTAL03 code. We have applied this method to the physisorption of the nitrogen mol.-in its ground and lowest-lying triplet states-on the (001) surface of hexagonal boron nitride. The semi-infinite crystal is simulated by slabs with different nos. of at. layers. [on SciFinder(R)]