Hi guys,

Rescently, I am reading the lammps codes for tip4p:

PairLJCutCoulLongTIP4P::PairLJCutCoulLongTIP4P(LAMMPS *lmp) :

PairLJCutCoulLong(lmp)

{

single_enable = 0;

// TIP4P cannot compute virial as F dot r

// due to find_M() finding bonded H atoms which are not near O atom

no_virial_compute = 1;

}

Can anyone tell me why we cannot calculate the virial as F dot r,if F is the force right on the oxygen or hydrogen atoms ?

Any help would be greatly appreciated.