def Lennard_Jones_AB(r, C6, C12, lam):
    """
    Computes the Lennard-Jones potential with C6 and C12 parameters

    Parameters
    ----------

    C6: float
        C6 parameter used for LJ equation
    C12: float
        C12 parameter used for LJ equation
    grid.ri: ndarray
        In the context of rism, ri corresponds to grid points upon which
        RISM equations are solved
    lam: float
        Lambda parameter to switch on potential

    Returns
    -------
    result: float
        The result of the LJ computation
    """

    return ((C12 / r ** 12) - (C6 / r ** 6)) * lam