Ab initio study of the 13C nuclear shieldings for some polyenals and their schiff bases using LORG theory
Ab initio LORG (localized orbital/local origin) shielding calculations were applied to some polyenes and their Schiff bases. Computations were performed as a function of basis set quality. The use of polarization functions in the shielding calculations for these highly polarizable compounds gives good agreement with the experimental values even for the carbonyl and the imine carbons.
Abstract A layer of random defects in the simple cubic Ising model with nearest neighbor ferromagnetic interactions of strength J is considered. Using the real space renormalization group method we calculate defect free energy in the whole temperature range. Specifically, we analyze: the layer of diluted defects, the layer of spin-glass type defects, and the layer of mixed defects. The free energy is strongly dependent on the value of couplings between the defect and the bulk.