Statistical weight of macrostate

If a physical system can be described as having several states which can be occupied by different numbers of particles but with the total number of particles being conserved and a condition that all allowed microstates of the closed system are equiprobable, the formula for the statistical weight of the system can be found in combinatorics.

Notes:

  1. Law can also be represented in form \(W = \frac{N!}{\prod_i (N_i!)}\) (W = factorial(N) / Product(factorial(N_i), i))

Links:

  1. Chemistry LibreTexts, formula 1.5.1.

statistical_weight

Statistical weight of the system’s macrostate.

Symbol:

W

particle_count_in_state

Number of particles in state \(i\).

Symbol:

N_i

Latex:

\(N_i\)

law

W = factorial(Sum(N_i, i)) / Product(factorial(N_i), i)

Latex:
\[W = \frac{(\sum_i N_i)!}{\prod_i (N_i!)}\]