MOLECULAR POLARIZABILITY AS A TOOL FOR UNDERSTANDING THE BINDING-PROPERTIES OF POLYCHLORINATED DIBENZO-P-DIOXINS - DEFINITION OF A RELIABLECOMPUTATIONAL-PROCEDURE

Molecular polarizability can be used to gain an insight into the origi ns of polychlorinated dibenzo-p-dioxins (PCDDs) specific binding to th eir receptor protein. In this work, the effects of the basis set on th e polarizability values calculated at the HF level of benzene, chlorob enzene, and dibenzo-p-dioxin (DD) are analyzed. The geometry optimized with the 3-21G basis set and polarizability calculated with the 6-31G (sd,sp) basis set give reliable values useful for comparing polarizabi lities of PCDDs with reduced computational costs. The study for two te trachlorodibenzo-p-dioxin isomers highlights interesting differences i n the molecular polarizability tensors as well as in the polarizabilit ies of C-Cl bonds related to the different chlorine positions on the a romatic skeleton.