INVESTIGATION OF ELECTRONIC INTERACTIONS IN SOLID HYDROGEN-FLUORIDE

Intermolecular interactions in solid hydrogen fluoride are studied by the combined quantum chemical and X-ray diffraction method. The struct ure of crystalline HF is modeled by (HF)(n) chains (n = 2,3,...,20), b y an (HF)(45) cluster consisting of five (HF)(9) chains, and by an (HF )(108) cluster consisting of twelve (HF)(9) chains with nearly zero di pole moment. The quantum chemical calculations of the clusters are per formed by the semiempirical AM1 method, which is most suitable for ele ctronic structure investigations of hydrogen fluoride, as shown by com paring the X-ray experimental and theoretical spectra. The theoretical X-ray spectra are also compared with the experimental FKalpha spectra of gaseous and solid hydrogen fluoride. For more detailed studies of electronic interactions in crystalline HF, fragment analysis of MOs of the clusters with respect to the MOs of the central molecule is carri ed out.