Texts: What is the difference between direct folding and exchange? Explain all the symbols of the equation.
Then, the total potential can be written as:
VDF(R) = VBF(R) + VPF(R) (11.13).
VBF(R) = Pp(rp)Pt(rt)VD(S)d3rpd3rt, S = rt - rp + R (11.14).
ik(R) 0p(rp, Tp + s)Pt(rt, rt - s)VEx(s)exp M FF(R) (11.15).
K2(R) = 2M[Ec.m - VPF(R) - VPF(R) - Vc(R)] (11.16).
Here, M = (Ap + AT).