Dear all,
I used the example in.gcmc.h2o provided with lammps-3Mar20 to look at water vapor at different pressures and also look at the condensation. the only modification I made to the file is replacing pressure as GMC input instead of mu (chemical potential).
I find a notable problem with lammps results:
At low vapor pressures, I always have one water molecule present in the box. This one molecule is present even when pressure is equal to zero. there are two problems with this. 1- no matter what the box size is this single molecule always stays which means we will have different vapor densities for a given pressure. 2- this result doesn’t match with what I get from Cassandra which agrees better with experimental results. In the case of GCMC with Cassandra, I get a box which depending on vapor pressure has one or no water molecules which gives on average the density of water vapor. the ever-present water molecule gives a very high density on average compared to expected results for SPCE.
I searched and played with the input file but still don’t find where the problem is. I would be very thankful if anyone can give me an insight into this problem. I send the input files with this email however nothing changes compare to the original file.
Best,
Ali Shomali
Department of mechanical and process engineering
ETHZ
H2O.txt (535 Bytes)
in.gcmc.h2o (2.59 KB)