Dear lammps researchers,
I want to calculate the PMF(free energy) of a gas molecule passing through the solution/vacuum interface using ‘fix smd’ command as (z direction considerd only):
fix 3 gas smd cvel K v tether NULL NULL z 0.0
How to determine the spring constant(K), the velocity of pulling(v) and the tether point(z), is there any menthods or suggestions? Besides, as the manual explains the last two output quantitie are the distance between the two reference points, and finally the accumulated PMF. Does the ‘distance between the two reference points’ stands for the distance between the tether point(if Ro=0) and the center of mass of group ‘gas’ ? Does the last ‘accumulated PMF’ is the PMF of the gas molecule along the passing coordinates ? Why it’s a ‘accumulated’ values?
Thank you very much in advance.