import math


def p_ws_from_t(t_celsius):
    """
    Calculate water vapor saturation pressure over liquid water for the temperature range of 0 to 200°C
    Eq (6) in "CHAPTER 6 - PSYCHROMETRICS" in "2001 ASHRAE Fundamentals Handbook (SI)"

    :param t_celsius: temperature [°C]
    :type t_celsius: double
    :return: water vapor saturation pressure [Pa]
    :rtype: double
    """

    # convert temperature
    t = t_celsius + 273.15

    # constants
    C8 = -5.8002206E+03
    C9 = 1.3914993E+00
    C10 = -4.8640239E-02
    C11 = 4.1764768E-05
    C12 = -1.4452093E-08
    C13 = 6.5459673E+00

    return math.exp(C8/t+C9+C10*t+C11*t**2+C12*t**3+C13*math.log1p(t))