Dear Sir,
I need some suggestion from you to solve my problem. In my system i have 2 types of atoms which is divided in 4 groups. active1, inactive1, active2, inactive2
Now i have to defined some kind of interaction when any atoms of active1 group come close to inactive1 group during the simulation (inter group interaction). After this interaction the atom of active1 will have to swap randomly with any atom of active2 group. Same as atom of inactive1 will swap randomly with atom of inactive2 group.
So, is there any command available in LAMMPS for such kind of interaction and swapping.
I was thinking about fix bond/create command to defined for such interaction.
But i have to define only for inter group. how can i do this?
Thanks.
Ankit Agrawal
IMSc India
Dear Sir,
I need some suggestion from you to solve my problem. In my system i have 2 types of atoms which is divided in 4 groups. active1, inactive1, active2, inactive2
Now i have to defined some kind of interaction when any atoms of active1 group come close to inactive1 group during the simulation (inter group interaction). After this interaction the atom of active1 will have to swap randomly with any atom of active2 group. Same as atom of inactive1 will swap randomly with atom of inactive2 group.
So, is there any command available in LAMMPS for such kind of interaction and swapping.
I don’t think so. You will likely have to write a custom fix that does what you want. You may want to have a look at fix gcmc as well as fix bond/create to see how parts of your problem are solved.
Thanks Axel for your suggestion. I implemented your suggestion to my LAMMPS script.
I have a group like this
group inactive0 type 1
group inactive1 type 2
group active0 type 3
group active1 type 4
group active_1_inactive_1 union active1 inactive1
and data header file like this
6098 atoms
6052 bonds
4 atom types
1 bond types
extra bonds per atom
-30.0 30.0 xlo xhi
…
Now when i am using this command
fix 4 active_1_inactive_1 bond/create 100 2 4 0.8 1 prob 0.5 85784 iparam 3 1 jparam 3 3
So, its giving error that “New bond exceeded special list size in fix bond/create (…/fix_bond_create.cpp:429)”
And when i changed one header line like
10 extra bonds per atom
Then it gives error “Unknown identifier in data file: 11 1 11 12”
In the tutorial it mentioned that for defining extra bond per atom = leave space for this many new bonds per atom.
I did the same thing but still getting error. Can you tell me what is the right way to define “extra bonds per atom”
Hey
Thanks Axel for your suggestion. I implemented your suggestion to my LAMMPS script.
That was not my suggestion
I have a group like this
group inactive0 type 1
group inactive1 type 2
group active0 type 3
group active1 type 4
group active_1_inactive_1 union active1 inactive1
and data header file like this
6098 atoms
6052 bonds
4 atom types
1 bond types
extra bonds per Atom
This is not correct. Please see the documentation.
-30.0 30.0 xlo xhi
…
Now when i am using this command
fix 4 active_1_inactive_1 bond/create 100 2 4 0.8 1 prob 0.5 85784 iparam 3 1 jparam 3 3
So, its giving error that “New bond exceeded special list size in fix bond/create (…/fix_bond_create.cpp:429)”
And when i changed one header line like
10 extra bonds per atom
Then it gives error “Unknown identifier in data file: 11 1 11 12”
This wrong, too.
In the tutorial it mentioned that for defining extra bond per atom = leave space for this many new bonds per atom.
I did the same thing but still getting error. Can you tell me what is the right way to define “extra bonds per atom”
The error is not about bonds, but exclusions. Again, please have a closer look at the manual.
I modified the input data like
6098 atoms
6052 bonds
4 atom types
2 bond types
6054 extra bonds per atom
now i am getting another error “1-3 bond count is inconsistent (…/special.cpp:287)”
scanning bonds …
3 = max bonds/atom
reading bonds …
6054 bonds
Finding 1-2 1-3 1-4 neighbors …
4 = max # of 1-2 neighbors
9 = max # of 1-3 neighbors
ERROR on proc 0: 1-3 bond count is inconsistent (…/special.cpp:287)
In my system there is no angle term then why am i getting this error. Do you have any clue?