CoachA microstate of a system of molecules is a complete specification of the state of every molecule. The statistical weight of a distribution of molecules over non-degenerate levels is the number of microstates that realise it:
Examples
Example 10.2 (Three quanta among three oscillators)
Three oscillators share three quanta of energy. The distribution “one oscillator holds all three” can be realised in ways, “one holds two, another one” in ways and “each holds one” in one way: ten microstates in all, and the most even distribution that still spreads the energy over several levels is the most probable. With molecules the weights become so sharply peaked that one distribution, and the ones that differ from it by a negligible amount, carry practically all the microstates.