Exact Equations for Taper Functions in Tersoff Potential


I want to implement the Tersoff bond order potential form in GULP. The manual indicates that there are three choices (cosine, mdf and murty) for the taper function f(r). I was wondering what are the exact equations for these taper funcrtions that are implemented in GULP. The form of the taper/cut-off function I am looking for is attached here. Is this form achievable in GULP?

Thanks for your help.


Tersoff bond order potentials are already implemented in GULP so need to implement them. The form of taper you are looking to use is essentially the
cosine one, since sin and cos are equivalent except for a phase shift. The
functional form of MDF is given in help.txt for cutp and the Murty form can be
found by looking for Kumagai et al and Tersoff, which is where this comes from.
You can also look in the code for a very precise description.