def es_pot(self, position):
    """
    Return the electorstatic potential generated by this Mol

    Parameters
    ----------
    position : 3x1 np array
        The point at which the potential should be evaluated
    Returns
    -------
    tot_pot : float
        The total potential

    """
    tot_pot = 0
    for atom in self:
        tot_pot += atom.es_pot(position)
    return tot_pot