The electronic spectrum of benzene

Assignment of the benzene spectrum is discussed using a new approach to the semi-empirical π-electron theory. The ordering ¹B_1u <¹E_1u <¹E_2g is shown to be theoretically preferred.     

Assignment of the electronic transitions in benzene

The problem of the assignment of π-electronic transitions in benzene is discussed using all criteria presently available. It is shown that based on this information a few different assignments are impossible to exclude. The correct assignment ³B_1u < ³E_1u < ¹B_2u < ³B_2u < ¹B_1u < ³E⁺_2g < ¹E_1u < ¹E^?_2g < ³E^?_2g has been selected as result of theoretical considerations based on a new approach to the semi-empirical π-electron theory. The results confirm the adequacy of the π-electron model for energy level calculations, and emphasise the fundamental importance of multi-excited configurations.     

New mineralogical phases identified by Mössbauer measurements in Morasko meteorite

The 0.9FeTiO₃–0.1Fe₂O₃ solid solution was prepared by solid state reaction with FeTiO₃ and α-Fe₂O₃ powders, and studied by x-ray diffraction, Mössbauer spectroscopy, and vibrating sample magnetometer (VSM). The crystalline structure was found to be single phase rhombohedral structure with lattice constant a?=?5.089 Å and c?=?14.051 Å. Mössbauer spectra of 0.9FeTiO₃–0.1Fe₂O₃ solid solution were taken at various temperatures ranging from 4.5 to 300 K. The anomalous absorption curves at low temperature are observed. Mössbauer spectra at 4.5 K was fitted to four six-line hyperfine pattern with magnetic hyperfine fields H _hf?=?504, 424, 115, and 58 kOe, respectively. At 40 K the spectrum shows the mixture of ferromagnetic six-line pattern and paramagnetic two-line and above 50 K it show asymmetry two-line patterns. The fitted curves at room temperature are obtained by superimposing two doublets corresponding to Fe^2?+ and Fe^3?+. The isomer shift δ and quadrupole splitting ΔE _Q of sample are 0.92 and 0.69 mm/s for Fe^2?+ and 0.14 and ??0.29 mm/s for Fe^3?+, respectively. Corresponding relative absorption subspectral areas are 89.2% for Fe^2?+ and 10.8% for Fe^3?+. Magnetization measurements indicate ferromagnetic behaviour with 92 Oe coercivity value at 50 K but at 300 K it show no hysteresis loop.     

The Influence of 5′,8-Cyclo-2′-deoxypurines on the Mitochondrial Repair of Clustered DNA Damage in Xrs5 Cells: The Preliminary Study

The 5′,8-cyclo-2′-deoxypurines (cdPus) affect the DNA structure. When these bulky structures are a part of clustered DNA lesions (CDL), they affect the repair of the other lesions within the cluster. Mitochondria are crucial for cell survival and have their own genome, hence, are highly interesting in the context of CDL repair. However, no studies are exploring this topic. Here, the initial stages of mitochondrial base excision repair (mtBER) were considered—the strand incision and elongation. The repair of a single lesion (apurinic site (AP site)) accompanying the cdPu within the double-stranded CDL has been investigated for the first time. The type of cdPu, its diastereomeric form, and the interlesion distance were taken into consideration. For these studies, the established experimental model of short oligonucleotides (containing AP sites located ≤7 base pairs to the cdPu in both directions) and mitochondrial extracts of the xrs5 cells were used. The obtained results have shown that the presence of cdPus influenced the processing of an AP site within the CDL. Levels of strand incision and elongation were higher for oligos containing RcdA and ScdG than for those with ScdA and RcdG. Investigated stages of mtBER were more efficient for DNA containing AP sites located on 5′-end side of cdPu than on its 3′-end side. In conclusion, the presence of cdPus in mtDNA structure may affect mtBER (processing the second mutagenic lesion within the CDL). As impaired repair processes may lead to serious biological consequences, further studies concerning the mitochondrial repair of CDL are highly demanded.     

Average energy of an N-electron system in a finite-dimensional and spin-adapted model space

An expression for the average energy of an N-electron system in a finite-dimensional, antisymmetric, and spin-adapted model space (as, e.g., a full-configuration interaction space) is derived using elementary properties of the Hamiltonian in the Fock space. © 1997 John Wiley & Sons, Inc.     

Analytical Solutions of the Schrödinger Equation with Power Potentials

Conditions for the existence of polynomial solutions of the Schrödinger equation with potentials which are linear combinations of powers of r ranging from ?2 to 2m, where m is a non‐negative integer, are derived and explicit expressions for the coefficients are given. Potentials with m = 0, 1, 2 are discussed in detail.     

Raman spectra of selected mineral phases of the Morasko iron meteorite

Selected minerals from oval inclusions (nodules) in the Morasko IAB iron meteorite have been investigated by electron microprobe (EMP) and micro‐Raman spectroscopy. Collected spectra of quartz, forsterite‐rich olivine, chromite, kosmochlor (Na–Cr‐rich clinopyroxene) and Na‐feldspar (albite) were compared with corresponding measurements of earth minerals and used for fast identification of meteorite fragments not EMP characterized. Some structural conclusions concerning particular minerals, like solid‐state form or average crystallite size, were also drawn from the measured spectra. Copyright © 2013 John Wiley & Sons, Ltd.     

A class of quantum fields constructed from Markoff fields

A class of fields with the mass parameter is constructed from Gaussian fields. The procedure of linearization of the Hamiltonian is shown to be equivalent to some linear transformation on the space indexing the Gaussian process.     

Regular restrictions of singular quadratic forms

Wroclaw University, Poland. Institute of Mathematics, Kiev, Ukraine. Translated from Funktsional'nyi Analiz i Ego Prilozheniya, Vol. 29, No. 2, pp. 79–81, April–June, 1995.     

Spectral density distribution of an N-electron Hamiltonian in a finite-dimensional and spin-adapted model space

Expressions for moments of spectral density distributions of a many-electron Hamiltonian defined in a finite-dimensional, antisymmetric, and spin-adapted model space (as, e.g., a full configuration interaction space) are derived. The moments are expressed in terms of combinations of two-electron integrals corresponding to a symmetric (a two-electron singlet) and antisymmetric (two-electron triplet) two-electron wave functions. A diagrammatic approach based on Hugenholtz-type diagrams and leading to a simple and universal classification scheme of the terms appearing in the expression for a specific moment is proposed. © 1995 John Wiley & Sons, Inc.