We demonstrate that the multipole polarizability tensors of a molecule are expressible as a sum of atomic contributions, each of which is based upon the change in the spatial distribution of electronic charge within each atom resulting from the application of electric fields and field gradients. The use of the spatially defined atoms of subsystem quantum mechanics correctly partitions molecular polarizabilities into physically meaningful atomic contributions. It is shown that the origin of any molecular polarizability tensor may be understood from an investigation of these contributions and the general expressions for the summation of atomic components to yield molecular polarizabilities are presented. Their use is demonstrated by the construction and investigation of the axial components of the dipole–dipole dipole–quadrupole, and quadrupole–quadrupole polarizability tensors of carbon monoxide and carbon sulfide. Key words: atomic polarizabilities, atoms-in-molecules, molecular polarizabilities.
(PPN)2C16S18 was obtained by the addition of PPN+Cl- to a methanolic extract of Na2C4Sx, derived from the reaction of C6S8O2 and NaOMe. Centrosymmetric C16S184- consists of thiophene units unsymmetrically fused to two 1,4-dithiin rings. Solutions of C16S184- convert to C8S82- with heating. When C4Sx (x ~ 8) is reduced by Na/NH3 followed by extraction and crystallization, one obtains the bicyclic polysulfide C4S82-, crystallized as its PPh4+ salt.
In order to treat wastewater rich in sulfate and organic carbon, an anaerobic attached-growth bioreactor was set up. It was the pretreatment of desulfurization-denitrification process. At hydraulic retention time of 128h-6.2h, sulfate removal rate and sulfide generating rate took on initial increasing and subsequent decreasing. At hydraulic retention time of 7.7h-10.2h, the removals of sulfate and organic carbon, sulfide generating rate reached 95.79%, 80% and 58.82%, respectively. The results showed that the suitable hydraulic retention time in sulfate reduction stage for the pretreatment of desulfurization-denitrification process was 7.7h-10.2h.
The carbon-sulfide-iron relationship and sulfate reduction rate in the East China Sea continental shelf sediments.
