Dear axel,
I am working with N2 + H2O mixtures. A slab of ice phase contacts with a slab of liquid H2O-N2 mixture (N2 molecules dissolved in liquid water). The mass of point charge/massless atom (at the center of N2) is set to 0.000000001. The angles and bonds of water molecules are constrained by SHAKE algorithm. When I use fix rigid/nvt for N2 group and fix nvt for water molecules group, the simulation runs very well. When I use fix rigid/npt for N2 group and fix npt for water molecules group. I got the error: Out of range atoms - cannot compute PPPM. That is to say, fix rigid/nvt can work yet fix rigid/npt can’t work with the same data file. However, when I leave out the ice phase, just run a simulation for liquid H2O-N2 mixture. I also use fix rigid/npt for N2 group and fix npt for water molecules group. The simulation runs well again. What could be the reason of this, what could I do? Thanks in advance for any support.
Dear axel,
I am working with N2 + H2O mixtures. A slab of ice phase contacts with
a slab of liquid H2O-N2 mixture (N2 molecules dissolved in liquid water).
The mass of point charge/massless atom (at the center of N2) is set to
0.000000001. The angles and bonds of water molecules are constrained by
SHAKE algorithm. When I use fix rigid/nvt for N2 group and fix nvt for water
molecules group, the simulation runs very well. When I use fix rigid/npt for
N2 group and fix npt for water molecules group. I got the error: Out of
range atoms - cannot compute PPPM. That is to say, fix rigid/nvt can work
yet fix rigid/npt can't work with the same data file. However, when I leave
out the ice phase, just run a simulation for liquid H2O-N2 mixture. I also
use fix rigid/npt for N2 group and fix npt for water molecules group. The
simulation runs well again. What could be the reason of this, what could I
do? Thanks in advance for any support.
you cannot have two integrators modify box size, i.e. not two npt
style integrators
at the same time. the simplest options is to use fix rigid/npt/small
for the entire system.