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Experimental and theoretical determination of the dipole polarizability of dibenzothiophene

Abstract:

The dipole polarizability of dibenzothiophene is reported, which was measured experimentally by refractometry techniques, and evaluated theoretically with ab initio and density functional theory (DFT) methods in the 1A′ electronic ground state. The experimental polarizability was determined from measurements of the refraction index of dibenzothiophene in CCl<inf>4</inf>-diluted solutions at five different frequencies to obtain the dispersion curve. The static polarizability of dibenzothiophene was determinated to be 2.358 × 10-23 esu from the extrapolation of the dispersion curve to zero frequency. Theoretical calculations were performed with fully C<inf>2v</inf> optimized geometries at both the HF/6-31G** and HF/6-31 + G(d,p) levels of theory, and we present comparisons with the crystal structure of dibenzothiophene and HF/6-31G** geometry of benzothiophene previously reported. We calculated the dipole polarizability by using the coupled perturbed Hartree-Fock analytical method, with both the STO/6-31 + G(d,p) and STO/6-31 + G(3d,3p) basis sets. We investigated the effects of exchange and electron correlation on these properties by using the BLYP and B3LYP hybrid approaches. The B3LYP/6-31 + G(3d,3p) average polarizability value of dibenzothiophene is 2.425 × 10-23 esu, which differs from the experimental static value by 3%. Copyright © 2001 John Wiley & Sons, Ltd.