vdw_lj_set Subroutine

private subroutine vdw_lj_set(params, eps, sigma, rcut)

Setter for 12-6 LJ (truncated & force-shifted) interaction.

The potential U is given by:

   V = 4*eps*[(r/sigma)^12 - (r/sigma)^6]  
   U = V - V(rcut) - (r - rcut)*dV/dr, r < rcut,
       0, r >= rcut  

where dV/dr is evaluated at r = rcut.

User-set parameters:

• params(1) = eps
• params(2) = sigma
• params(3) = rcut

Internally stored parameters:

• params(4) = V(rcut)
• params(5) = dV/dr(rcut)

Arguments