Thanks for answering my email so quickly.

I build a test case that has four atoms. The group1 includes atoms of type 1,2, and the group2 includes atoms of type 3,4.

input file:

dimension 3

units metal

boundary p p p

atom_style full

neighbor 3.0 bin

neigh_modify delay 0 every 1 check yes

read_data coh5.data

bond_style harmonic

bond_coeff 1 23.983 0.96

pair_style hybrid/overlay lj/cut 10.0 hbond/dreiding/lj 4 3.3 3.5 150

pair_coeff 1 1 lj/cut 0.0074 3.12

pair_coeff 3 3 lj/cut 0.0074 3.12

pair_coeff 1 3 lj/cut 0 3.12

pair_coeff 1 2 lj/cut 0.0025 2.0054

pair_coeff 1 4 lj/cut 0 2.0054

pair_coeff 2 3 lj/cut 0 2.0054

pair_coeff 3 4 lj/cut 0.0025 2.0054

pair_coeff 2 2 lj/cut 8.6738e-4 0.8909

pair_coeff 4 4 lj/cut 8.6738e-4 0.8909

pair_coeff 2 4 lj/cut 0 0.8909

pair_coeff 1 3 hbond/dreiding/lj 2 i 0.412 2.75 4 3.3 3.5 150

pair_coeff 1 3 hbond/dreiding/lj 4 j 0.412 2.75 4 3.3 3.5 150

region r1 block INF INF INF INF INF 0.3 units box

region rt block INF INF INF INF 0.3 INF units box

group group2 region r1

group group1 region rt

variable fg1x equal fcm(group1,x)

compute hb all pair hbond/dreiding/lj

variable nhb equal c_hb[1]

variable ehb equal c_hb[2]

compute gg2 group1 group/group group2

timestep 0.001

thermo_style custom v_fg1x c_gg2[1] c_hb[2] c_hb[1] c_gg2

thermo 1

run 1

Results:

fg1x gg2[1] hb[2] hb[1] gg2

1.7759315 0.003058996 -0.72879179 2 -0.40814027

1.7759315 0.003058996 -0.72879179 2 -0.40814027

The v_fg1x is not equal to c_gg2[1] while I expect that interaction between group1 and group2 is only hbond/dreiding/lj.

1、

pair_coeff 1 3 hbond/dreiding/lj 2 i 0.412 2.75 4 3.3 3.5 150

#pair_coeff 1 3 hbond/dreiding/lj 4 j 0.412 2.75 4 3.3 3.5 150

Results:

fg1x gg2[1] hb[2] hb[1] gg2

1.7990464 0.003058996 -0.40814027 1 -0.40814027

1.7990464 0.003058996 -0.40814027 1 -0.40814027

The v_fg1x is not equal to c_gg2[1] even if c_hb[2] is equal to c_gg2. The group/group includes all the energy from hbond/dreiding/lj?

2、

#pair_coeff 1 3 hbond/dreiding/lj 2 i 0.412 2.75 4 3.3 3.5 150

pair_coeff 1 3 hbond/dreiding/lj 4 j 0.412 2.75 4 3.3 3.5 150

Results:

fg1x gg2[1] hb[2] hb[1] gg2

1.8134486 0 -0.32065152 1 0

1.8134486 0 -0.32065152 1 0

Now the group/group doesn’t include the energy from hbond/dreiding/lj. Maybe there is something different between donor flag i and j.

3、

#pair_coeff 1 3 hbond/dreiding/lj 2 i 0.412 2.75 4 3.3 3.5 150

#pair_coeff 1 3 hbond/dreiding/lj 4 j 0.412 2.75 4 3.3 3.5 150

Results:

fg1x gg2[1] gg2

1.8365636 0 0

1.8365636 0 0

I can’t find what results in the force v_fg1x. Does the force in the group has any effect?

4、

bond_style harmonic

bond_coeff 1 0 0.96

pair_style hybrid/overlay lj/cut 10.0 hbond/dreiding/lj 4 3.3 3.5 150

pair_coeff 1 1 lj/cut 0 3.12

pair_coeff 3 3 lj/cut 0 3.12

pair_coeff 1 3 lj/cut 0 3.12

pair_coeff 1 2 lj/cut 0 2.0054

pair_coeff 1 4 lj/cut 0 2.0054

pair_coeff 2 3 lj/cut 0 2.0054

pair_coeff 3 4 lj/cut 0 2.0054

pair_coeff 2 2 lj/cut 0 0.8909

pair_coeff 4 4 lj/cut 0 0.8909

pair_coeff 2 4 lj/cut 0 0.8909

pair_coeff 1 3 hbond/dreiding/lj 2 i 0.412 2.75 4 3.3 3.5 150

pair_coeff 1 3 hbond/dreiding/lj 4 j 0.412 2.75 4 3.3 3.5 150

results:

fg1x gg2[1] hb[2] hb[1] gg2

-0.060632104 0.003058996 -0.72879179 2 -0.40814027

-0.060632104 0.003058996 -0.72879179 2 -0.40814027

I think there is interaction of only hbond/dreiding/lj style. The inconsistency still exists, and the v_fg1x is quite different from that in the previous results.

Thanks,

Erchia

oh4.in (1.32 KB)

coh5.data (455 Bytes)