Set two atom types for O and H in one system

LAMMPS LAMMPS Mailing List Mirror
1

Dear users,

I want to study the movement of two layers of water in on simulation system. So I set different types for O and H in the input file. The water model is TIP4P. There is copper in the system, so hybrid potential pair styles are used as below:

pair_style hybrid lj/cut/tip4p/long 2 3 1 1 0.125 12.0 lj/cut/tip4p/long 4 5 2 2 0.125 12.0 eam

But I got the error below:

pair_coeff 1 1 eam Cu_u3.eam
Reading potential file Cu_u3.eam with DATE: 2007-06-11
pair_coeff 2 2 lj/cut/tip4p/long 7.0575098e-3 3.16435
ERROR: Expected integer parameter in input script or data file (…/pair_hybrid.cpp:383)

Is it possible to set different types for the same atom in lammps?

Best,
Shiwei

2

Dear users,

I want to study the movement of two layers of water in on simulation
system. So I set different types for O and H in the input file. The water
model is TIP4P. There is copper in the system, so hybrid potential pair
styles are used as below:

pair_style hybrid lj/cut/tip4p/long 2 3 1 1 0.125 12.0 lj/cut/tip4p/long
4 5 2 2 0.125 12.0 eam

But I got the error below:
pair_coeff 1 1 eam Cu_u3.eam
Reading potential file Cu_u3.eam with DATE: 2007-06-11
pair_coeff 2 2 lj/cut/tip4p/long 7.0575098e-3 3.16435
ERROR: Expected integer parameter in input script or data file
(../pair_hybrid.cpp:383)

Is it possible to set different types for the same atom in lammps?

​yes, it is. you have to watch out, though, when using the same pair style
twice in a hybrid pair style. then the syntax for labeling sub-styles
changes slightly.
more importantly, you will not be able to specify the interactions between
the two groups of TIP4P water molecules correctly, thus i would recommend
to specify the pair style only once and use some other indicated, e.g. the
molecule id to differentiate between the atoms in those layers

axel.

3

Hi Axel,

Thanks a lot. I am trying to use atom ID and molecule ID.

Best,
Shiwei