def guggenheim_katayama(target, K2, n, temperature='pore.temperature',
    critical_temperature='pore.critical_temperature', critical_pressure=
    'pore.critical_pressure'):
    """
    Missing description

    Parameters
    ----------
    target : OpenPNM Object
        The object for which these values are being calculated.  This
        controls the length of the calculated array, and also provides
        access to other necessary thermofluid properties.

    K2 : scalar
        Fluid specific constant

    n : scalar
        Fluid specific constant

    temperature : string
        The dictionary key containing the temperature values (K)

    critical_temperature : string
        The dictionary key containing the critical temperature values (K)

    critical_pressure : string
        The dictionary key containing the critical pressure values (K)

    Returns
    -------
    value : NumPy ndarray
        Array containing surface tension values [N/m]

    """
    T = target[temperature]
    Pc = target[critical_pressure]
    Tc = target[critical_temperature]
    sigma_o = K2 * Tc ** (1 / 3) * Pc ** (2 / 3)
    value = sigma_o * (1 - T / Tc) ** n
    return value
