something wrong in NPT

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1

Dear all,

I got a problem in NPT simulation.

'fix 2 part2 npt temp 300.0 300.0 10.0 z 1000.00 1000.00 10.0 dilate partial '.

Then, I got the temperature for part 2 fluctuate at 350K(it should be 300K) but for all of the atoms (part1+part2), the temperature fluctuate at 300K. What’s going on?

Here, the atoms in part 2 are fixed with the command 'fix 1 par1 setforce 0 0 0 '.

Thanks,

Hangyan

2011-09-22

2

Dear all,

I got a problem in NPT simulation.

'fix 2 part2 npt temp 300.0 300.0 10.0 z 1000.00 1000.00 10.0 dilate partial
'.

Then, I got the temperature for part 2 fluctuate at 350K(it should be 300K)
but for all of the atoms (part1+part2), the temperature fluctuate at 300K.

which temperature, i.e. how computed?

What's going on?

how should i be able to tell from just one line of your input?
most likely you are not computing the temperature right.

there are extensive discussions of how thermostats work
and what "temperature" is show how and where in the
lammps manual.

Here, the atoms in part 2 are fixed with the command
'fix 1 par1 setforce 0 0 0 '.

since you are only time integrating the part2 group atoms,
how would this have any impact?

axel.