Dear lammps users and Ray Shan,
I am trying to use QEq to calculate charges of atoms. When the Taper upper radius is 10 A the charges are meaningless (I mean they are so high, +3, -5, etc). When I decrease its value the charges are better.
I also tried to reproduce the QEq charges of some molecules (H2O, CH4, HF) reported in the original paper of QEq (The Journal of Physical Chemistry 95 (1991) 3358-3363) and I got the similar results when the upper Taper radius is around 2 A.
I did all simulations with k-space switched off.
What should the upper Taper radius value be?
cheers.
baris