Showing papers in "The Journal of Physical Chemistry in 1967"

Rare earths. iv. dissociation energies of the gaseous monoxides of the rare earths.

Abstract: : The dissociation energy of the gaseous rare earch monoxides together with the closely related compounds ScO and YO were determined from Knudsen effusion and mass spectrometric isomolecular oxygen-exchange reaction studies. It is shown that there is a double periodicity in the variations of the dissociation energies with atomic number and that these variations closely match those of the heats of sublimation of the rare earth metals. Assuming a common bound state for the monoxides, M++O--, it is shown that the variations in the dissociation energies in the lanthanide series correspond to the magnitude of the 4f(n) to 4f(n-1)5d transitions of the divalent ions. (Author)9

Infrared spectra and the thermodynamics of alcohol- hydrocarbon systems

Abstract: The concentrations of various alcohols in ethanol-n- heptane and ethanol-toluene solutions over the temperature range of 20-50$ were determined from an analysis of infrared spectral data in the frequency range of the hydroxyl stretching mode and by using heat-of-mixing data. With this analysis, it was possible to determine the portion of the heat-of-mixing that resulted from hydrogen-bond rupture. By using these results, the hydrogen-bond energy was found to be about 5.2 kcal/mole of bonds, and the interaction energy between the hydroxyl and the pi electrons of toluene was about 2.0 kcal/mole of bonds. The infrared spectral analysis method used did not provide suitable data for the calculation of Gibbs free energy and entropy. (12 refs.)