def Van_der_Waals_volume(R):
return R*<NUM_LIT><EOL>
r'''Calculates a species Van der Waals molar volume with the UNIFAC method,
    given a species's R parameter.

    .. math::
        V_{wk} = 15.17R_k

    Parameters
    ----------
    R : float
        R UNIFAC parameter (normalized Van der Waals Volume)  [-]

    Returns
    -------
    V_vdw : float
        Unnormalized Van der Waals volume, [m^3/mol]

    Notes
    -----
    The volume was originally given in cm^3/mol, but is converted to SI here.

    Examples
    --------    
    >>> Van_der_Waals_volume(4.4998)
    6.826196599999999e-05

    References
    ----------
    .. [1] Wei, James, Morton M. Denn, John H. Seinfeld, Arup Chakraborty, 
       Jackie Ying, Nicholas Peppas, and George Stephanopoulos. Molecular 
       Modeling and Theory in Chemical Engineering. Academic Press, 2001.