Refine pair coeff

LAMMPS LAMMPS Beginners
1

Hello,

I currently have a Lammps input file with water and oxygen gas. This input file has 1500 hydrogen and oxygen water atoms, set at variety of coordinates within the box.

My issue is that my hydrogens have been assigned # pair coeff 1 and my water oxygen have been assigned # pair coeff 2. These coefficient numbers are maintained throughout the 1500 atoms—every time a hydrogen is indicated, it is labelled pair coeff 1, and every tume a oxygen atom is indicated, it is labelled pair coeff 2.

Is there any way to switch the pair coeff numbers for all the oxygen and hydrogens?

2

One number is as good as the other. Why do you need to change them?

3

I thought TIP4P required that the oxygen come first and the hydrogen second?

4

In the data file, yes. Ordered by atom ID. Atom types are irrelevant in that regard.