Dear all,

I am trying to compute the density of water. For a start I have just used a

very small box consisting of 703 molecules. Using the NPT, I find that the

box size increases dramatically ( nearly 200 times larger in each

dimension), then reduces and increases again. The simulation becomes

extremely slow. I started off with the correct box size for the density of

water at 1 atm pressure, so I would expect to recover approximately this box

size.

Is there something wrong with my input ? I am using TIP4P to model the water

molecules. Attached are my input files

Thanks

Huck Beng

in.swnt_c (1.04 KB)

data.swnt (215 KB)