Negative enthalpy values in log file

Hello LAMMPS users,
I ran a simulation in which the command “thermo_style” was used:
thermo_style custom step temp press vol enthalpy
The enthalpy column has all negative values as given below:
Is there something wrong with my system or it’s not unusual?
Thanks.for your help.

“enthalpy” is nothing else but “etotal + press*vol”, so depending on the pressure and/or total energy it can be either positive or negative. Since the absolute value of “etotal” has no meaning for classical potentials, also the absolute value of “enthalpy” has no meaning.

Thus from the sign of either “etotal” or “enthalpy” no conclusions can be drawn. You simulation can be bogus or proper, you’ll have to use other parameters to determine which.