Hi,

I would like to equilibrate a polymer system. Right now, my strategy is to build an amorphous cell at reduced density (0.4, about half of actual) then run dynamics at 600 K for 600 ps in he NPT ensemble then run for 600 ps at 300 K to get the properties I want.

However, Jawalkar et al J. Phys. Chem. B 2007, 111, 2431-2439, used the NVT ensemble at a specified density, which they got from the literature. They did not do the 600 k equilibration

I have two questions:

1. I find the 600 K equilibration changes the results at 300 K but I did not check carefully - is equilibrtion at 600 K important for large molecules?

2. If I want to go from an NPT trajecory to NVT, how can I adjust the cell volume to the density I want to run the NVT at?

Thank you in advance,

Constantine