Determination of Some Descriptors of the Real World Working on the Fundamental Identity of the Basic Concept and the Origin of the Electronegativity and the Global Hardness of Atoms. Part 2: Computation of the Dipole Moments of Some Heteronuclear Diatomics

To garner further support of our conjecture that "the electronegativity and the hardness manifest two different descriptors of the one and the same fundamental property of atoms," we have derived a formula of evaluating the dipole charge of heteronuclear diatomic molecules, A-B, in terms of the global hardness of the atoms as: q = a (Delta eta/eta(A)) + b, where, a and b are two constants, q is the dipole charge, Delta eta is the hardness difference of the two atoms A and B, and eta(A) is the hardness of the harder atom. In deriving the above formula, we have relied upon the fact that hardness, similar to the electronegativity, controls the physical process of charge rearrangement during the chemical event of molecule formation. We have calculated the dipole charge and dipole moment of as many as 39 different types of compounds of widely divergent physico-chemical behavior in terms of the algorithm derived in the present work. The computed dipole charge and dipole moment reveals the known chemico-physical behavior of such compounds under study. A comparative study of the nature of variation of theoretically evaluated and experimentally determined dipole moments plotted in as many as six figures reveal that there is an excellent agreement between the two sets of dipole data. Hence, the ansatz suggested for the calculation of the dipole charge in terms of the hardness data of the atoms forming the compound is extremely efficacious in computing the charge distribution. It further transpires that the assumed model of charge rearrangement during the event of molecule formation is realistic and supports our basic conjecture that operationally the two descriptors, the hardness and the electronegativity, are identical. (C) 2010 Wiley Periodicals, Inc. Int J Quantum Chem 111: 2802-2810, 2011