[lammps-users] units metal / real for TIP4P

Dear lammps users

I am having some trouble with the units conversion. I understand that the parameters for the TIP4P water potential are given in real units. However, I have to convert the units to metal, since I will also use the AIREBO potential.

In doing so, I realize that the results are different. Am I missing something? Attached are both input files for real/metal units.

Thanks.

Huck Beng

data.metal_units (66.7 KB)

in.metal_units (873 Bytes)

data.real_units (66.7 KB)

in.real_units (970 Bytes)

2008/6/23 Chew Huck Beng <[email protected]…786…>:

Dear lammps users

I am having some trouble with the units conversion. I understand that the parameters for the TIP4P water potential are given in real units. However, I have to convert the units to metal, since I will also use the AIREBO potential.

In doing so, I realize that the results are different. Am I missing something? Attached are both input files for real/metal units.

You may be using the wrong conversion factor (it should be 1 kcal/mol = 0.04337 eV); I get a value of 0.007253 eV for epsilon instead of 0.006998 eV.

–AEI

Your timestep in both input files is 1.0. That's 1 fmsec
in real units, but 1 psec in metal units.

Steve