dihedral.py

#!/usr/bin/env python

import numpy as np
from matplotlib import pyplot as plt


def dihedral_pot(phi, v_barrier=1., n=3., phase=0., divider=1.):
    return v_barrier * (1. + np.cos(n * phi - phase)) / divider


phi = np.linspace(0., 2. * np.pi, num=50)
energy = dihedral_pot(phi) + dihedral_pot(phi, n=1.)

plt.plot(phi, energy, 'b--')
plt.show()