Experimental and theoretical determination of the dipole polarizability ofdibenzothiophene

The dipole polarizability of dibenzothiophene is reported, which was measur ed experimentally by refractometry techniques, and evaluated theoretically with ab initio and density functional theory (DFT) methods in the (1)A' ele ctronic ground state. The experimental polarizability was determined from m easurements of the refraction index of dibenzothiophene in CCl4-diluted sol utions at five different frequencies to obtain the dispersion curve. The st atic polarizability of dibenzothiophene was determinated to be 2.358 x 10(- 23) esu from the extrapolation of the dispersion curve to zero frequency. T heoretical calculations were performed with fully C-2V optimized geometries at both the HF/6-31G** and HF/6-31 + G(d,p) levels of theory, and we prese nt 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 metho d, with both the STO/6-31 + G(d,p) and STO/6-31 + G(3d,3p) basis sets. We i nvestigated the effects of exchange and electron correlation on these prope rties by using the BLYP and B3LYP hybrid approaches. The B3LYP/6-31 + G(3d, 3p) average polarizability value of dibenzothiophene is 2.425 x 10(-23) esu , which differs from the experimental static value by 3%. Copyright (C) 200 1 John Wiley & Sons, Ltd.