The Temperature Variation of Some Thermodynamic Quantities

摘要

The quantity, (F0—E00)/T,calculated from spectroscopic data has been fitted to a five constant equation inTfor 19 molecules. It may be differentiated and integrated to give values ofS0,E0,H0andCp0between 298.1 and 3000°K and is sufficiently exact for most purposes. The equilibrium constant for exchange reactions involving isotopes has been calculated and in each case, maxima exist and in one case a minimum also. This effect probably occurs at some temperature for all reactions involving isotopic molecules although not for other equilibria. An optimum temperature therefore exists for separation of isotopes by exchange reactions.