Hi
I want to calculate the electrostatic interactions energy between two groups of particles. Thus, I have used two commands in my input script
Pair_style lj/cut/coul/long 12 12
Pair_modify lj/cut compute no (or mix arithmetic compute no)
Kspace_style pppm 0.0001
As we know, pair energy = evdw+elong+ecoul and electrostatic energy = elong + ecoul. In this case, as I am omitting the vdw interaction energy by pair_modify lj/cut compute no , is it only calculating the electrostatic energy? Or to calculate the only electrostatic energy i should use this command: pair_style mix arithmetic compute no? Please advise.
If I do simulation only with pair_style coul/long 12, i am getting error like this-
PPPM initialization …
using 12-bit tables for long-range coulomb (src/kspace.cpp:321)
G vector (1/distance) = 0.20238
grid = 24 24 30
stencil order = 6
estimated absolute RMS force accuracy = 0.00899096
estimated relative force accuracy = 2.7076e-05
using double precision FFTs
3d grid and FFT values/proc = 12958 4608
ERROR: All pair coeffs are not set (src/pair.cpp:225)
Last command: run 50000