Python/physics/translation_partition

import math

def translation_partition_function(mass: float, temperature: float, 
                                   volume: float) -> float:
    """
    Calculates the translational partition 
    function using the formula:
    q_trans = ((2 * pi * m * k_B * T)^(3/2) * V) / h^3

    mass: Mass of the molecule in kg
    temperature: Temperature in Kelvin
    volume: Volume in cubic meters

    >>> round(translation_partition_function(2e-26, 300, 1e-3), 4)
    4.081816847078438e+28
    >>> round(translation_partition_function(4e-26, 300, 1e-3), 4)
    1.1545121488522627e+29
    >>> round(translation_partition_function(-4e-26, 300, 1e-3), 4)
    Traceback (most recent call last):
        ...
    ValueError: Mass must be positive
    >>> round(translation_partition_function(4e-26, 0, 1e-3), 4)
    Traceback (most recent call last):
        ...
    ValueError: Temperature must be positive
    >>> round(translation_partition_function(4e-26, 300, 0), 4)
    Traceback (most recent call last):
        ...
    ValueError: Volume must be positive
    """

    if mass <= 0:
        raise ValueError("Mass must be positive")
    if temperature <= 0:
        raise ValueError("Temperature must be positive")
    if volume <= 0:
        raise ValueError("Volume must be positive")

    h = 6.62607015e-34  # Planck's constant in J·s
    k_B = 1.380649e-23  # Boltzmann constant in J/K

    prefactor = (2 * math.pi * mass * k_B * temperature) ** (3 / 2)
    denominator = h ** 3
    return (prefactor * volume) / denominator

if __name__ == "__main__":
    import doctest
    doctest.testmod(name="translation_partition_function")