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Full-Text Articles in Chemistry
Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner
Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner
Steve Scheiner
A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of [MTPP]x ions (x = 2+, 1+, 1−, 2−, 3−, 4−), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as 3A2g, which arises from the configuration (dxy)2(dz …
Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner
Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner
Steve Scheiner
The electronic structure and bonding in a series of unligated and ligated FeII porphyrins (FeP) are investigated by density functional theory (DFT). All the unligated four-coordinate iron porphyrins have a 3A2g ground state that arises from the (dxy)2(dz2)2(dπ)2 configuration. The calculations confirm experimental results on Fe tetraphenylporphine but do not support the resonance Raman assignment of Fe octaethylporphine as 3Eg, nor the early assignment of Fe octamethyltetrabenzporphine as 5B2g. For the six-coordinate Fe–P( …
Using An Expectation‐Maximization Algorithm To Obtain Dielectric Relaxation Time Spectra Ofaqueous Montmorillonite Clay Suspensions, Stephen E. Bialkowski, Lynn Dudley, Dani Or
Using An Expectation‐Maximization Algorithm To Obtain Dielectric Relaxation Time Spectra Ofaqueous Montmorillonite Clay Suspensions, Stephen E. Bialkowski, Lynn Dudley, Dani Or
Stephen E. Bialkowski
Determination of relaxation-time distributions from dielectric spectra of complex impedance or dielectric permittivity remains a challenge. This problem is one of a wider class of ill-posed inverse problems where the measurement is a superposition or convolution of functions containing the sought-after information. An expectation-maximization (EM) algorithm is shown to be useful for obtaining dielectric relaxation-time distributions from impedance data. This algorithm is stable and converges to realistic relaxation-time spectra without the need for constraints or initial values. The implementation used herein updates expectations in an iterative multiplication step. The models and basic assumptions of impedance spectroscopy are outlined in the …
Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner
Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of [MTPP]x ions (x = 2+, 1+, 1−, 2−, 3−, 4−), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as 3A2g, which arises from the configuration (dxy)2(dz …
Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner
Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
The electronic structure and bonding in a series of unligated and ligated FeII porphyrins (FeP) are investigated by density functional theory (DFT). All the unligated four-coordinate iron porphyrins have a 3A2g ground state that arises from the (dxy)2(dz2)2(dπ)2 configuration. The calculations confirm experimental results on Fe tetraphenylporphine but do not support the resonance Raman assignment of Fe octaethylporphine as 3Eg, nor the early assignment of Fe octamethyltetrabenzporphine as 5B2g. For the six-coordinate Fe–P( …