I am trying to equilibrate a water droplet. The system consists of 2440 water molecules (SPC/E). I am using Shake to constrain the water molecules. An equilibration run was run 100ps (fix nve with fix temp/rescale) fixing the temperature at 220K. Following that, when I try to run a constant energy simulation (removing temp/rescale), the particle seems to have equilibrated (temp fluctuates about 220K). However the potential energy (and as a result, the total energy) seems to be all over the place.
Step Temp PotEng KinEng TotEng
0 220.64311 -25249.309 3208.8949 -22040.415
10 220.09195 -24686.818 3200.8791 -21485.939
20 218.81464 -18948.086 3182.3028 -15765.783
30 220.07978 -18136.302 3200.7022 -14935.6
Obviuosly I am doing something wrong. I am attaching the input script. If required, I can email the data file.
Any help would be hugely appreciated.
in.waterFAtestNVE (1.03 KB)