diff --git a/physics/translation_partition b/physics/translation_partition new file mode 100644 index 000000000..865d77b06 --- /dev/null +++ b/physics/translation_partition @@ -0,0 +1,48 @@ +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")