ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The Törring–Ernst–Kindt (TEK) model for the alkaline-earth monohalide molecules was extended to predict molecular polarizabilities and quadrupole moments in addition to dipoles. Calculations were carried out for the 19 molecules for which experimental bond lengths and vibrational frequencies are known. It was found that for many of these molecules the TEK model predicts negative polarizability anisotropies, α⊥〉α(parallel). This is in disagreement with the dipole-induced dipole, or Silberstein, formula, but in agreement with an empirical correlation between the anisotropy and the molecular asymmetry noted by Winicur. The TEK polarizabilities give rise to a much smaller second-order Legendre anisotropy in the CaCl–Ar interaction potential than was found in earlier work using the Rittner model. The D-shell model applied earlier to the alkali halides was also applied to the 19 alkaline-earth monohalides. With a slight modification it was found to describe both classes of ionic compounds successfully, although less successfully for the alkaline-earth compounds. The D-shell model was shown to be a generalization of the TEK model which includes the effect of the shell overlap on the polarizing fields at the ions. Nevertheless, the TEK model predicts better dipole moments, unless the shell charge is treated as an additional, adjustable parameter in the D-shell model.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.455112
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