[lammps-users] pair write shows difference between lj/cut/coul/cut and lj/cut/coul/long

Hi all,

When I was trying to check my pair_coeff, I plotted the potential function u® according to the analytical form and then compared with the result given by pair_write.
lj/cut/coul/cut is the same as the analytical plot while lj/cut/coul/long is not. For lj/cut/coul/long, the minimum energy is about 6ev higher. Here is how I set the potential:

pair_style lj/cut/coul/long 10.0 10.0
#pair_style lj/cut/coul/cut 10.0 10.0
pair_coeff 1 1 0.00145 1.98
pair_coeff 2 2 0.00128 5.24
pair_modify shift yes mix arithmetic
kspace_style ewald/n 1.0e-8
pair_write 1 2 1000 r 1.8 10.0 table.txt LJ_Coul 1.18 -1.18

Is there anything wrong with my kpace setting?

Those are 2 different pair potentials, with different
analytic forms, so I'm not clear why you expect them
to be the same. Also, if you use shift yes, you will
be shifting the LJ portion, which may confuse the