MONOTONIC BEHAVIOUR OF DATA FOR MAIN-GROUP TRIATOMIC MOLECULES
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Date
1990
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Ohio State University
Abstract
We are investigating the data for a variety of properties for main-group, neutral, ground-state triatomic molecules. We are seeking a simple combination of the row numbers with respect to which the data will be on smooth, monotonic (in the same direction, increasing or decreasing, for a given property) curves for all group-number combinations and for the all properties. We have been guided by (1) a conviction that the function will reduce to $R_{1}\ast R_{2}$, with which data for diatomic molecules correlate impressively $well,^{1}$ or $R_{1}+R_{2}$, with which they correlate somewhat less well,1 when one atomic row number is removed; by (2) studies on the asymptotic behaviours of various properties in the heavy-molecule limit2; and by (3) the hypothesis that the function should not treat differently the central of the three atoms. We have investigated the functions $R_{1}+R_{2}+R_{3}, R_{1}^{\ast}R_{2}^{\ast}R_{3}$, and $R_{1}^{\ast}R_{2}+R_{1} {^{\ast}}R_{3}+R_{2}{^{\ast}}R_{3}$, to which criterea (1) and (3) pertain; we will try others. We are doing this for dissociation energy, partition function, and equilibrium constant $data,^{3}$ and for ionization $potential^{4}$ and entropy $data,^{5}$ for growing number of column-number combiinations (such as 7,2,7 -- alkaline-earth dihalides including such molecules as C1FMg). We are aware that an empirical search such as this can never be totally convincing, but some of our plotted curves appear to be predictively useful
Description
$^{1}$ R. Hefferlin, ``Periodic Systems and their Relation to the Systematic Analysis of Molecular Data,'' Edwin Mellen Press, Lewiston, NY, 1989. $^{2}$ J. F. Mucci and N. H. March, J. Chem. Phys. 82, 5099 (1985). $^{3}$ A. J. Sauval, unpublished communication. $^{4}$ L. V. Gurvich et al, Energii Razryva Khimicheskikh Svyazei, Nauka, 1974. $^{5}$ K. S. Krasnov et al, Molekulyarnye Postoyannye Neorganicheskikh Soedineni, Khimiya, 1979.
Author Institution: Physics Department, Southern College
Author Institution: Physics Department, Southern College