Dear Lammps users,
According to the following file I am trying to do the first 2 step of Thermal conductivity calculation of water.( from the kappa example of lammps).
But both f_hot and f_cold are calculated negative for me in the second step.
Do someone has any experience to help me to see what is the reason.
I have changed the size of box and the position of hot and cold in different ways…but that’s not the reason.
Thanks in advance
This example can’t be used without the datafile, however, the problem is probably that when you use “localised” thermostats for rigid water the number of degrees of freedom will be wrong.
When you use SHAKE, each of your water molecules loses 3 degrees of freedom (we can portion this into . If the entire system is thermostatted, then these lost degrees of freedom are accounted for. When only portions of the system are thermostatted, however, they are not. You have to adjust the target temperatures for both thermostats to account for the fact that the water molecules do not have as many degrees of freedom as LAMMPS expects.
Thank you very much for your help and suggestion.Regards