def press_Davison_1968(t_k):
    """From Davison

    Parameters
    ----------
    t_k, K

    Returns
    -------
    Vapor pressure, Pa

    References
    ----------
    Davison, H.W.
    "Complication of Thermophysical Properties of Liquid Lithium."
    NASA Technical Note TN D-4650. Cleveland, Ohio: Lewis Research Center, July 1968.

    Notes
    -----
    "With this equation the data shown in figure 8 are correlated
     with a standard deviation of 3.38 percent. The maximum deviation
     of -32.6 percent occurred at a vapor pressure of about 6 Pa."

    The plot Figure 8 shows 800 to 1800 K so we can take that as the applicable range.
    """
    return 10**(10.015 - 8064.5 / t_k)