Statistical Weight


statistical weight

[stə′tis·tə·kəl ′wāt] (statistics) A number assigned to each value or range of values of a given quantity, giving the number of times this value or range of values is found to be observed. (statistical mechanics) The number of microscopic states that correspond to a given macroscopic state. A multiplicative factor in the expression for the probability of finding a system in a given quantum state, usually equal to the number of degenerate substates contained in the state.

Statistical Weight

 

In quantum mechanics and quantum statistical mechanics, the statistical weight is the number of different quantum states with a given energy—that is. the degree of degeneracy. If the energy assumes a continuous series of values, the statistical weight is understood as the number of states in a given energy range. In classical statistical mechanics, the size of a volume element of phase space is sometimes called the statistical weight.