The Determination of Energy Levels from Thermodynamic Data. II. The Heights of Potential Energy Barriers Restricting Intramolecular Rotation
- 1 May 1950
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 18 (5) , 630-636
- https://doi.org/10.1063/1.1747713
Abstract
The uncertainty in the distribution of the energy levels implies a corresponding uncertainty in the shape of the associated potential energy function. The estimation of barrier heights is known to depend upon the shape of the potential, therefore implicitly upon the energy level distribution. We apply these ideas to the restricted rotation problem by introducing a shape parameter into the assumed potential function, and show that the currently accepted barrier height ranges should be widened. On the basis of our modified function, we found the following barrier heights to be consistent with published thermodynamic data: ethane 1550 to 2700 calories per mole; 1,1,1‐trifluoroethane 2300 to 8300; methanol 800 to 3000.Keywords
This publication has 30 references indexed in Scilit:
- Repulsive Forces in Relation to Bond Energies, Distances and Other PropertiesJournal of the American Chemical Society, 1948
- The Heat Capacity, Heats of Transition, Fusion and Vaporization, Vapor Pressure and Entropy of 1,1,1-TrifluoroethaneJournal of the American Chemical Society, 1944
- The Raman EffectReviews of Modern Physics, 1943
- Influence of barrier dimensions on the vibrational spectrum of ethaneProceedings of the Physical Society, 1942
- The Heat Capacity of Organic Vapors. I. Methyl AlcoholJournal of the American Chemical Society, 1941
- Internal Rotation and Resonance in HydrocarbonsJournal of the American Chemical Society, 1939
- RESTRICTED INTERNAL ROTATION IN HYDROCARBONSJournal of the American Chemical Society, 1938
- Thermodynamic Functions for Molecules Having Restricted Internal RotationsThe Journal of Chemical Physics, 1937
- Calculation of Characteristic Values for Periodic PotentialsPhysical Review B, 1933
- THE HEAT CAPACITY OF METHYL ALCOHOL FROM 16°K. TO 298°K. AND THE CORRESPONDING ENTROPY AND FREE ENERGYJournal of the American Chemical Society, 1929