compute group/group error for LJ interactions.

Hi All,

I’m simulating a carbon nanotube in water and I’m trying to calculate the interaction energy between CNT and water using group/group command but I’m getting the error - Pair hybrid-sub style does not support single call.

I know the group/group command can’t be used with rebo or dsf, but here I’m calculating the simple LJ interaction energy between CNT and water.

The relevant parts of the script is

group water type 1 2
group gnc type 3

pair_style hybrid lj/cut/coul/dsf 0.025 12.0 12.0 rebo
pair_coeff * * lj/cut/coul/dsf 0.0 0.0
pair_coeff 2 2 lj/cut/coul/dsf 0.15535 3.166
pair_coeff 2 3 lj/cut/coul/dsf 0.09369 3.19
pair_coeff * * rebo inputFiles/CH.airebo_real NULL NULL C

compute eng gnc group/group water
variable
​ ​
eng1 equal c_eng
fix
​ ​
fxprnt1 all print 10 “${eng1}” file data.dat screen no

Any ideas ?

Hi All,

I’m simulating a carbon nanotube in water and I’m trying to calculate the interaction energy between CNT and water using group/group command but I’m getting the error - Pair hybrid-sub style does not support single call.

I know the group/group command can’t be used with rebo or dsf, but here I’m calculating the simple LJ interaction energy between CNT and water.

The relevant parts of the script is

group water type 1 2
group gnc type 3

pair_style hybrid lj/cut/coul/dsf 0.025 12.0 12.0 rebo
pair_coeff * * lj/cut/coul/dsf 0.0 0.0
pair_coeff 2 2 lj/cut/coul/dsf 0.15535 3.166
pair_coeff 2 3 lj/cut/coul/dsf 0.09369 3.19
pair_coeff * * rebo inputFiles/CH.airebo_real NULL NULL C

compute eng gnc group/group water
variable
​ ​
eng1 equal c_eng
fix
​ ​
fxprnt1 all print 10 “${eng1}” file data.dat screen no

Any ideas ?

Compute group/group cannot know which pair of types and thus has to assume the worst. The best way to deal with it, is to record the trajectory and then use rerun for analysis, where you remove the airebo potential.

Axel