All pair coeffs are not set

LAMMPS LAMMPS General Discussion
1

ERROR: All pair coeffs are not set (src/pair.cpp:249)
Last command: run ${nNPT}
srun: error: amr-168: tasks 0-15: Exited with exit code 1

Im using Lamps aug 2023 version and got this error if you please can help me address it.
pair_coeff 18 9 lj/cut/coul/long 0 0
pair_coeff 14 14 lj/cut/coul/long 0.066 3.5
pair_coeff 1 1 lj/cut/coul/long 0.066 3.5
pair_coeff 2 2 lj/cut/coul/long 0.066 3.5
pair_coeff 3 3 lj/cut/coul/long 0.066 3.5
pair_coeff 4 4 lj/cut/coul/long 0.066 3.5
pair_coeff 14 5 lj/cut/coul/long 0.044497 2.95804
pair_coeff 14 6 lj/cut/coul/long 0.083247 3.6349
pair_coeff 14 7 lj/cut/coul/long 0.117729 3.163858
pair_coeff 14 8 lj/cut/coul/long 0.105925 3.372684
pair_coeff 5 5 lj/cut/coul/long 0.03 2.5
pair_coeff 5 6 lj/cut/coul/long 0.056126 3.07051
pair_coeff 5 7 lj/cut/coul/long 0.079373 2.673948
pair_coeff 5 8 lj/cut/coul/long 0.071414 2.850439
pair_coeff 6 6 lj/cut/coul/long 0.105 3.75
pair_coeff 6 7 lj/cut/coul/long 0.148492 3.285803
pair_coeff 6 8 lj/cut/coul/long 0.133604 3.502678
pair_coeff 7 7 lj/cut/coul/long 0.21 2.96
pair_coeff 7 8 lj/cut/coul/long 0.188944 3.04877
pair_coeff 8 8 lj/cut/coul/long 0.17 3.25
pair_coeff 9 9 lj/cut/coul/long 0.0 0.0
pair_coeff 10 11 lj/charmm/coul/charmm 0 0
pair_coeff 10 10 lj/charmm/coul/charmm 0.1553978 3.166
pair_coeff 11 11 lj/charmm/coul/charmm 0 0
pair_coeff 14 10 lj/charmm/coul/charmm 0.101241296 3.328813602
pair_coeff 5 10 lj/charmm/coul/charmm 0.068256868 2.813360979
pair_coeff 6 10 lj/charmm/coul/charmm 0.127696907 3.445649431
pair_coeff 7 10 lj/charmm/coul/charmm 0.180590697 3.061267711
pair_coeff 8 10 lj/charmm/coul/charmm 0.162483845 3.207725051
pair_coeff 9 10 lj/charmm/coul/charmm 0.0 0.0
pair_coeff 1*9 11 lj/cut/coul/long 0.0 0.0

and
atom_style full
units real
bond_style harmonic
angle_style harmonic
dihedral_style opls
improper_style harmonic
special_bonds lj/coul 1e-20 1e-20 0.5
pair_style hybrid lj/cut/coul/long 10.0 10.0 lj/charmm/coul/charmm 9.0 10.0
pair_modify pair lj/cut/coul/long special lj/coul 0.0 0.0 0.5
pair_modify pair lj/charmm/coul/charmm special lj/coul 0.0 0.0 0.0
kspace_style pppm 0.0001

2

The error message is pretty self-explanatory. You can use the info coeffs command to narrow down which pair coeffs are missing.

3

Thank you for your reply ,using the command showed that all coeffs are not set even though I did set them previosely,is that due to the init setting and hybrid style?

Pair Coeffs:
1 1: is not set
1 2: is not set
1 3: is not set
1 4: is not set
1 5: is not set
1 6: is not set
1 7: is not set
1 8: is not set
1 9: is not set
1 10: is not set
1 11: is not set
2 2: is not set
2 3: is not set
2 4: is not set
2 5: is not set
2 6: is not set
2 7: is not set
2 8: is not set
2 9: is not set
2 10: is not set
2 11: is not set
3 3: is not set
3 4: is not set
3 5: is not set
3 6: is not set
3 7: is not set
3 8: is not set
3 9: is not set
3 10: is not set
3 11: is not set
4 4: is not set
4 5: is not set
4 6: is not set
4 7: is not set
4 8: is not set
4 9: is not set
4 10: is not set
4 11: is not set
5 5: is not set
5 6: is not set
5 7: is not set
5 8: is not set
5 9: is not set
5 10: is not set
5 11: is not set
6 6: is not set
6 7: is not set
6 8: is not set
6 9: is not set
6 10: is not set
6 11: is not set
7 7: is not set
7 8: is not set
7 9: is not set
7 10: is not set
7 11: is not set
8 8: is not set
8 9: is not set
8 10: is not set
8 11: is not set
9 9: is not set
9 10: is not set
9 11: is not set
10 10: is not set
10 11: is not set
11 11: is not set

4

I don’t see the specification of the coefficients for the interaction 1-2 for example in your script.

Maybe if you specify them in some sort of order, it would be easier for you. Like

1 1
1 2
1 3
1 4
(…)
1 11
2 2
(…)
2 11
(…)

5

It is very likely that you meant to use hybrid/overlay rather than hybrid. A hybrid style means that all pairs must have coefficients for both styles because both styles will be applied at once to all pairs. As an example, hybrid lj/cut ... coul/long is essentially the same as lj/cut/coul/long.

If (I suspect) you are mixing two force-fields, one with lj/cut* and one with lj/charmm*, then you are looking for hybrid/overlay, where some pairs will use the first style, some pairs the second, and unspecified pairs will not have an interaction.

6

This is incorrect. Pair style hybrid is exclusive but hybrid/overlay may use multiple pair styles for the same pair style (but does not have to). Because of the latter behavior, mixing rules are applied differently and it is highly recommended to provide explicit parameters for all pairs of atom types.

In general, it is not a good idea to mix and match different force fields, especially not if they are using different conventions for assigning charges and LJ parameters like CHARMM and OPLS.

7

Yikes – I had those exactly backwards. Thanks!