Showing papers by "Willis B. Person published in 1963"

Electron Affinities of Some Halogen Molecules and the Charge‐Transfer Frequency

Abstract: In an attempt to fix the value of the vertical electron affinity of the iodine molecule EI2v the potential curve for I2— has been constructed from semiempirical considerations. From this curve the value of EI2v is estimated to be 1.7±0.5 eV, in apparent contradiction to the value around 0 eV indicated by the electron‐capture experiments. It is suggested that the electron‐capture experiment may measure the vertical energy for capture to give an excited state of the I2— ion, thus explaining the discrepancy.Having fixed the value for EI2v, the relationship predicting the charge transfer frequency for iodine complexes is reexamined critically. By fitting curves to the data for three different types of complexes (π donors with I2, amine donors with I2, and complexes with I atoms), three sets of empirical constants required to force the fit are determined. An attempt is then made to calculate these sets of constants from a priori considerations. The success of this treatment supports the general theory, indicat...

Absolute Infrared Intensities in Some Crystalline Hydrogen Halides

Abstract: Absolute intensities of the fundamental vibrational bands of HCl and HBr have been measured in the absorption spectrum of crystalline films. The path length has been determined from the interference fringes of the transmitted light as the film is deposited on a window, following the technique of Hollenberg and Dows. The measured integrated molar absorption coefficients B are 24 000±3000 and 17 600±1200 darks (cm—1cm2/mM), respectively, for HCl and HBr. These values are larger than the gas phase intensities by factors of 6 and 13, respectively. Such large intensification of an X—H stretching vibration is consistent with the large frequency shift and is characteristic of hydrogen‐bonded crystals. The results are compared with those from other hydrogen‐bonded systems. Furthermore, the high intensities are consistent with those required by Hornig and Hiebert using the transition dipole—transition dipole model to explain the observed intermolecular force constants. However, it is likely that other terms contri...