Dear SIESTA users, I want to do Van der waals dispersion correction using SIESTA. I have used a dispersion potential of Grimme type as suggested in Grimme's paper (J. Comput. Chem. Vol 27, 1787-1799 (2006)). My system is a carbon nanotube and nitrogen molecule is confined within it. I have prepared the input as given below. %block MM.Potentials 1 1 Grimme 60.710 5.488 carbon carbon 1 2 Grimme 60.710 5.384 carbon nitrogen %endblock MM.Potentials
MM.Grimme.D 20.0 MM.Grimme.S6 1.66 MM.Cutoff 30. Bohr Now my queries are: (1). Whether I have to consider the interaction between nitrogen-nitrogen and nitrogen-carbon also? (2). Should I use the original Grimme parameter value as given in the paper or I have to multiply it by 34.69142857 as mentioned in siesta-l? (3). If I substitute one carbon atom in the nanotube by any impurity atom then what are the interactions between the atoms (carbon, nitrogen, impurity atom) that I have to consider?
