AB-INITIO QUANTUM-CHEMICAL CALCULATIONS OF GEOMETRY AND VIBRATIONAL FREQUENCIES OF CHLORINE HEPTOXIDE

Ab initio force fields for the vibrations of Cl2O7 in its ground elect ronic state have been determined at the Hartree-Fock level using the 6 -31G basis set. The calculated geometries of Cl2O7 at HF/6-31G* and M P2/6-31G have been compared with the corresponding X-ray crystallogra phic structure. The calculated vibrational frequencies of Cl2O7 are di scussed in comparison to those determined from experiment and to the c orresponding quantities for some similar molecules of the type ClO3-O- X (X is F, Cl, Br, H).