def LK_omega(Tb, Tc, Pc):
T_br = Tb/Tc<EOL>omega = (log(<NUM_LIT>/Pc) - <NUM_LIT> + <NUM_LIT>/T_br + <NUM_LIT>*log(T_br) -<EOL><NUM_LIT>*T_br**<NUM_LIT:6>)/(<NUM_LIT> - <NUM_LIT>/T_br - <NUM_LIT>*log(T_br) +<EOL><NUM_LIT>*T_br**<NUM_LIT:6>)<EOL>return omega<EOL>
r'''Estimates the acentric factor of a fluid using a correlation in [1]_.

    .. math::
        \omega = \frac{\ln P_{br}^{sat} - 5.92714 + 6.09648/T_{br} + 1.28862
        \ln T_{br} -0.169347T_{br}^6}
        {15.2518 - 15.6875/T_{br} - 13.4721 \ln T_{br} + 0.43577 T_{br}^6}

    Parameters
    ----------
    Tb : float
        Boiling temperature of the fluid [K]
    Tc : float
        Critical temperature of the fluid [K]
    Pc : float
        Critical pressure of the fluid [Pa]

    Returns
    -------
    omega : float
        Acentric factor of the fluid [-]

    Notes
    -----
    Internal units are atmosphere and Kelvin.
    Example value from Reid (1987). Using ASPEN V8.4, LK method gives 0.325595.

    Examples
    --------
    Isopropylbenzene

    >>> LK_omega(425.6, 631.1, 32.1E5)
    0.32544249926397856

    References
    ----------
    .. [1] Lee, Byung Ik, and Michael G. Kesler. "A Generalized Thermodynamic
       Correlation Based on Three-Parameter Corresponding States." AIChE Journal
       21, no. 3 (1975): 510-527. doi:10.1002/aic.690210313.