For the copper(@ carboxylate dimer C U ~( R C O ~) ~, the exchange parameter J [ = $(Esinglet-Etrjplet)] is calculated using a simplified INDO molecular orbital procedure with configuration interaction. The primary calcula?ion utilizes ten atomic orbitals, namely the metal-ion 3d,~-~2 orbitals and an sp2 hybrid orbital from each oxygen atom of the four carboxy!ate ligands. Using limited and complete configuration interaction procedures, values of -80 and -130 cin-I are calculated for the exchange parameter. Some lNDO calculations with two rather than four RCO, ligands indicate that overlap between the two oxygen orbitals of each carboxylate ligand, rather thanthecopperdx2-y2 -dx2 -y z 8-typeoverlap, is of primary importance for determining themagnitude of the exchange parameter. This 0-0 overlap becomes effective because the oxygen lone-pair electrons are calculated to delocalize appreciably into the singly-occupied Cu(n) orbitals.For the lowest-energy S = 0 and S = 1 states of the dimer with two carboxylate ligands, the weights for all valence-bond structures are calculated from the complete configuration-interactioii wave-functions. The valence-bond structure with a Cu-Cu &bond in the S = 0 state is found to have a small weight. The importance of the 0-0 overlap for antifcrromagnetism is deduced from valence-bond resonance considerations.
11-1* For valence-bond structures (2)-(4), 3, 1 and 1 other mirror-image structures exist. In fig. 2, the structural weights are for all equivalent structures taken together.
This work describes the application of a parameter determination methodology to complicated multicomponent systems with a focus on developing pyrolysis models that can predict fire response as a function of the material composition. Thermogravimetric analysis, differential scanning calorimetry, microscale combustion calorimetry, an absorption coefficient measurement, and radiationdriven gasification experiments were conducted on fiberglass reinforced unsaturated polyester composites comprised of various ratios of matrix to reinforcement phases to fully parameterize the pyrolysis model. A single set of properties was defined for each of the reinforcement and matrix phases and the properties were validated against experimental data collected outside the model calibration conditions. This study demonstrated the ability of a pyrolysis model, parameterized through a systematic methodology, to produce pyrolyzate gas production rate predictions for the composites to within 20% of the experimental measurements and emphasized the implications for the use of pyrolysis models in the design of composites.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.