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Chemistry and Biochemistry Faculty Publications

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Structure

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Articles 1 - 5 of 5

Full-Text Articles in Physical Sciences and Mathematics

Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner Jan 2002

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 Jan 2002

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( …


Electronic Structure And Bonding In Metal Phthalocyanines, Metal=Fe, Co, Ni, Cu, Zn, Mg, M.-S. Liao, Steve Scheiner Jan 2001

Electronic Structure And Bonding In Metal Phthalocyanines, Metal=Fe, Co, Ni, Cu, Zn, Mg, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Electronic structure and bonding in metal phthalocyanines (Metal=Fe, Co, Ni, Cu, Zn, Mg) is investigated in detail using a density functional method. The metal atoms are strongly bound to the phthalocyanine ring in each case, by as much as 10 eV. The calculated orbital energy levels and relative total energies of these D4h structures indicate that Fe and Co phthalocyanines have 3A2g and 2Eg ground states, respectively, but that these states are changed upon interaction with strong-field axial ligands. The valence electronic structures of Fe and Co phthalocyanines differ significantly from those of …


Structure, Energetics, And Vibrational Spectrum Of H2o–Hcl, Z. Latajka, Steve Scheiner Jan 1987

Structure, Energetics, And Vibrational Spectrum Of H2o–Hcl, Z. Latajka, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

H2O–HCl is studied using a number of basis sets including 6‐31G∗∗ and variants which are augmented by a diffuse sp shell and a second set of d functions on O and Cl. Optimization of the geometry of the complex is carried out including explicitly electron correlation and counterpoise correction of the basis set superposition error (BSSE) at both the SCF and correlated levels. Correlation strengthens and shortens the H bond while BSSE correction leads to an opposite trend; these two effects are of different magnitude and hence cancel one another only partially. ΔH°(298 K) is …


Role Of D Functions In Ab Initio Calculation Of The Equilibrium Structure Of H2s–Hf, Steve Scheiner Jan 1983

Role Of D Functions In Ab Initio Calculation Of The Equilibrium Structure Of H2s–Hf, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Full geometry optimizations are performed to determine the equilibrium geometry of the hydrogen‐bonded complex H2S–HF. The angle between the plane of the H2S moiety and the H‐bond axis calculated with the 4–31 G basis set is 106° as compared to the experimental value of 91±5°. This quantity is reduced significantly when d orbitals are added to the basis set, yielding an angle within experimental error of 91°. (AIP)