Hi all,
I want to model water with TIP4P and with SHAKE to constraint the angle and bond, and with Lammps framework I have not got any problem for that. But furthermore I want to see shock wave propagation through water. Would it be conceptually correct to use SHAKE during shock run ?
I was trying with and without SHAKE by “momentum mirror” method but in both cases faced some problem.
With SHAKE the computed temperature value (temp/com) differs so much with experimental and also the value got from MSST simulation. Is it due to the additional force which constraints the bond and angle affect the velocity, so then temperature ? Computed stress (after safely subtracting off the com velocity) also differs.

When i was trying without shake, after some steps simulation stops and the error was “Out of range atoms - cannot compute PPPM”

Any suggestion and discussion would be a great help for me.

Hi all,
I want to model water with TIP4P and with SHAKE to constraint the angle and
bond, and with Lammps framework I have not got any problem for that. But
furthermore I want to see shock wave propagation through water. Would it be
conceptually correct to use SHAKE during shock run ?
I was trying with and without SHAKE by "momentum mirror" method but in both
cases faced some problem.
With SHAKE the computed temperature value (temp/com) differs so much with
experimental and also the value got from MSST simulation. Is it due to the
additional force which constraints the bond and angle affect the velocity,
so then temperature ? Computed stress (after safely subtracting off the com
velocity) also differs.

When i was trying without shake, after some steps simulation stops and the
error was "Out of range atoms - cannot compute PPPM"

Any suggestion and discussion would be a great help for me.

there is not enough information for any serious comments.

Thanks for your attention. Actually as far I understand that using SHAKE means, it will enforce the atoms to constraint the bonds and angles by applying some additional force. This additional force will affect the velocity vectors of atoms and consequently temperature and pressure also. My doubt is how can I exclude that perturbation to compute the unaffected T and P during the dynamics of the system over time ?

My another question, is it conceptually correct to use SHAKE during a NEMD simulation ?