[ESPResSo-users] LJ anisotropic potential

[Damian]

Hello guys!

 

I’m trying to modify the code for the Lennar-Jones anisotropic potential (LJangle.cpp,hpp) but I can’t get how the gradient of potential is implemented, I mean

 

The potential is in the form U(r,theta1,theta2)=  dU/dr *  r_unitary + dU/dtheta1 * theta1_unitary + dU/dtheta2 * theta2_unitary

 

And I can’t figure it out how the vectors theta1_unitary and theta2_unitary were calculated.

 

Thanks in advance.