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100th anniversary of the Sackur–Tetrode equation
Author(s) -
Grimus Walter
Publication year - 2013
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201300720
Subject(s) - mercury (programming language) , monatomic gas , physics , theoretical physics , quantum mechanics , computer science , programming language
In 1912, Otto Sackur and Hugo Tetrode independently put forward an equation for the absolute entropy of a monoatomic ideal gas and published it in "Annalen der Physik." The grand achievement in the derivation of this equation was the discretization of phase space for massive particles, expressed as \delta q \delta p = h, where q and p are conjugate variables and h is Planck's constant. Due to the dependence of the absolute entropy on Planck's constant, Sackur and Tetrode were able to devise a test of their equation by applying it to the monoatomic vapor of mercury; from the satisfactory numerical comparison of h obtained from thermodynamic data on mercury with Planck's value from black-body radiation, they inferred the correctness of their equation. In this review we highlight this almost forgotten episode of physics, discuss the arguments leading to the derivation of the Sackur--Tetrode equation and outline the method how this equation was tested with thermodynamic data.