Dear Axel,
I want to know whether it is make sense to use the 3- or 4 order of the polynomial to fit the stiffness vs length.
For the 4 order polynomial (command "fitsvsl -f -op=4"), the miscibility gap decreases and I have good result. In the case of linear fitting, the miscibility gap donot decrease but increase (compare to the one without vibrations effect).
It looks like the stiffness and length obey the linear relation within the range of nearest neighbor (about 2.6 angstrom), but tend to be a 4 order to a large distance (3.1 ansgstrom). I cannot find the use of higher order fitting in the literatures, except the use of second order fitting in the Cu-Li system.So I am not sure the 4 order fitting make sense in the Length Dependent Transferable method. And Is there a command in the "fitsvsl" which can be used to cut the fitting distance just as the one (-fr) in the "fitfc". Thanks.
Regards,
wz chen