CCl 4: mean dipole moment derivatives and core electron binding energies

Abstract

Atomic polar tensors for the carbon tetrachloride molecule are calculated from experimental fundamental infrared intensities, a normal coordinate transformation determined from observed fundamental frequency values and experimentally determined CCl bond lengths. Dipole moment derivative sign ambiguities were eliminated by comparing the alternative mathematical solutions obtained from the experimental data with results of Hartree–Fock, Möller–Plesset 2 and Density Functional Theory calculations using a 6−31++G(d,p) basis set. Carbon and chlorine mean dipole moment derivatives of 1.043±0.022e and −0.261±0.006e, respectively, are determined from the preferred atomic polar tensors. These values are in excellent agreement with those obtained from the CCl 4 1s carbon atom ionization energy using a simple potential model (1.081e and −0.270e), from an electronegativity model proposed earlier (1.008e and −0.252e) and from an electronegativity equalization model (1.066e and −0.266e).