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Current advances in molecular magnetism are aimed at the construction of molecular nanomagnets and spin qubits for their utilization as high-density data storage materials and quantum computers. Mononuclear coordination compounds with low spin values of

We present a study of the annealing effect and its influence on magnetic and structural properties for a series of Heusler alloys Ni50−xCoxMn35.5In14.5 (x=0,3,5) prepared in ribbon form. We studied the morphology and composition using scanning electron microscopy (SEM) equipped with an X-ray microanalyzer (EDX). The magnetic properties were determined by two methods: electron magnetic resonance (EMR) and vibrating sample magetometer (VSM). We found that cobalt content in the annealed samples reveals an additional magnetic phase transition at lower temperatures.

Current advances in molecular magnetism are aimed at the construction of molecular nanomagnets and spin qubits for their utilization as high-density data storage materials and quantum computers. Mononuclear coordination compounds with low spin values of S=½ are excellent candidates for this endeavour, but their construction via rational design is limited. This particularly applies to the single copper(II) spin center, having been only recently demonstrated to exhibit slow relaxation of magnetisation in the appropriate octahedral environment. We have thus prepared a novel, modular organic scaffold that would allow one to gain in-depth insight into how purposeful structural differences affect the slow magnetic relaxation in monometallic, transition metal complexes. As a proof-of-principle, we demonstrate how one can construct two, structurally very similar complexes with isolated Cu(II) ions in an octahedral ligand environment, the magnetic properties of which differ significantly. The differences in structural symmetry effects and in magnetic relaxation are corroborated with a series of experimental and theoretical techniques, showing how symmetry distortions and crystal packing affect the relaxation behaviour in these isolated Cu(II) systems. Our highly modular organic platform can be efficiently utilized for the construction of various transition-metal ion systems in the future, effectively providing a model system for investigation of magnetic relaxation via targeted structural distortions.

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 &lt, x &lt, 0.08) were measured with a dependence on temperature (82 K &lt, T &lt, 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.

This paper presents electron magnetic resonance (EMR) and vibrating sample magnetometry (VSM) study of Heusler alloy Ni 50 Mn 35.5 In 14.5 ribbons prepared by melt spinning. The temperature dependency of the EMR spectra and magnetization was measured during the cooling and heating process in the 180–330 K and 100–450 K temperature ranges, respectively. Both methods reveal thermal hysteresis (structural phase transition) and metamagnetic character of this material. The morphology and composition were investigated by scanning electron microscopy (SEM) with an energy-dispersive spectrometer (EDS).

This paper contains a detailed study of low-field microwave absorption, which is observed in EMR spectra registered for a series of Ni50−xCoxMn35.5In14.5 (x=0,3,5) Heusler alloys polycrystalline in situ and annealed at 1173 K ribbons. The LFMA spectra for all ribbons were performed at X-band (∼9.5 GHz), at temperatures below Curie temperature. Additionally, for annealed Ni45Co5Mn35.5In14.5 ribbons, the LFMA signal dependencies of the external magnetic field modulation amplitude, modulation frequency, microwave power and microwave magnetic field phase were registered. These results confirm the resonant character of LFMA. To determine the basic EMR parameters, such as linewidth and resonance field, the experimental data were fitted by the Dyson function. The LFMA signal is satisfactorily matched by the two lines, and the variability of the component lines with temperature is remarkable.

A modification of the ABTS• decolorization assay for plate readers is presented. In our modification, 200 µL of ABTS solution of absorbance 1.0 at 734 nm was added with an antioxidant and decreased absorbance resulted. For comparison of antioxidant activities in the kinetic assay of absorbance decrease, concentration dependence of absorbance decrease and of area under curve are recommended. “Fast” and “slow” antioxidants were distinguished: while the reactions of “fast” antioxidants ABTS• were completed within seconds, the reactions of “slow” antioxidants were not finished after 6 min. We recommend reaction time of 60 min for assays of such antioxidants, blood plasma and plant extracts. Sub-additive interactions between some antioxidants (ascorbate and Trolox, hispidulin and Trolox, and glutathione and ascorbate) were found in the ABTS• decolorization; possible reasons for such interactions are discussed.

In this work, we present the results of defects analysis concerning ZnO and Al2O3 layers deposited by atomic layer deposition (ALD) technique. The analysis was performed by the X-band electron paramagnetic resonance (EPR) spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods. The layers were either tested as-deposited or after 30 min heating at 300 °C and 450 °C in Ar atmosphere. TEM and XPS investigations revealed amorphous nature and non-stoichiometry of aluminum oxide even after additional high-temperature treatment. EPR confirmed high number of defect states in Al2O3. For ZnO, we found the as-deposited layer shows ultrafine grains that start to grow when high temperature is applied and that their crystallinity is also improved, resulting in good agreement with XPS results which indicated lower number of defects on the layer surface.

The aim of this study was to characterize the interaction of chosen catechins ((+)-catechin, (&ndash, )-epigallocatechin (EGC), and (&ndash, )-epigallocatechin gallate (EGCG)) with human erythrocytes and their protective effects against oxidative damage of erythrocytes. Uptake of the catechins by erythrocytes was studied by fluorimetry, their interaction with erythrocyte membrane was probed by changes in erythrocyte osmotic fragility and in membrane fluidity evaluated with spin labels, while protection against oxidative damage was assessed by protection against hemolysis induced by permanganate and protection of erythrocyte membranes against lipid peroxidation and protein thiol group oxidation. Catechin uptake was similar for all the compounds studied. Accumulation of catechins in the erythrocyte membrane was demonstrated by the catechin-induced increase in osmotic resistance and rigidification of the erythrocyte membrane detected by spin labels 5-doxyl stearic acid and 16-doxyl stearic acid. (&ndash, )-Epigallocatechin and EGCG inhibited erythrocyte acetylcholinesterase (mixed-type inhibition). Catechins protected erythrocytes against permanganate-induced hemolysis, oxidation of erythrocyte protein thiol groups, as well as membrane lipid peroxidation. These results contribute to the knowledge of the beneficial effects of catechins present in plant-derived food and beverages.

Magnetic properties and exchange bias of $$\hbox { Ni}_{45}\hbox {Co}_{5}\hbox {Mn}_{35.5}\hbox {In}_{14.5}$$ ribbons were investigated by vibrating sample magnetometry (VSM) and electron magnetic resonance (EMR). Curie temperatures determined by using VSM and EMR methods are equal to 374 K and 377 K, respectively. Additionally, the EMR measurements revealed the existence of a weak ferromagnetic resonance (FMR) line in the paramagnetic region. The upward deviation of the integral intensity from Curie–Weis low below temperature $$T^*$$ and above $$T_\mathrm{C}$$ confirms the existence of ferromagnetic phase in this temperature region. Below $$T_\mathrm{C},$$ the integral intensity does not saturate, which can suggest the coexistence of different magnetic phases at low temperature range. Additional confirmation on the coexistence of magnetic phases in the sample are asymmetric hysteresis loops associated with the spontaneous exchange bias effect. The dependence of EMR signal on cyclic repetition of measurement is also discussed.

We have studied magnetic properties of zinc oxide (ZnO) composite doped with Co ions. The samples were obtained by pulsed laser deposition (PLD) method. Electron magnetic resonance (EMR) measurements were carried out and temperature dependence of EMR spectra was obtained. Analysis of temperature dependence of the integral intensity of EMR spectra was carried out using Curie-Weiss law. Reciprocal of susceptibility of an antiferromagnetic (AFM) material shows a discontinuity at the Néel temperature and extrapolation of the linear portion to negative Curie temperature. The results of temperature dependence of EMR spectra for the ZnO:Co sample and linear extrapolation to the Curie-Weiss law indicated the AFM interaction between Co ions characterized by the Néel temperatures TN = 50 K and TN = 160 K for various samples. The obtained g-factor is similar to g-factors of nanocrystals presented in literature, and the results confirm that in the core of these nanocrystals Co was incorporated as Co2+, occupying Zn2+ sites in wurtzite structure of ZnO.

Parkinson’s disease (PD) patients can benefit from antioxidant supplementation, and new efficient antioxidants are needed. The aim of this study was to evaluate the protective effect of selected nitroxide-containing redox nanoparticles (NRNPs) in a cellular model of PD. Antioxidant properties of NRNPs were studied in cell-free systems by protection of dihydrorhodamine 123 against oxidation by 3-morpholino-sydnonimine and protection of fluorescein against bleaching by 2,2-azobis(2-amidinopropane) hydrochloride and sodium hypochlorite. Model blood-brain barrier penetration was studied using hCMEC/D3 cells. Human neuroblastoma SH-SY5Y cells, exposed to 6-hydroxydopamine (6-OHDA), were used as anin vitromodel of PD. Cells were preexposed to NRNPs or free nitroxides (TEMPO or 4-amino-TEMPO) for 2 h and treated with 6-OHDA for 1 h and 24 h. The reactive oxygen species (ROS) level was estimated with dihydroethidine 123 and Fluorimetric Mitochondrial Superoxide Activity Assay Kit. Glutathione level (GSH) was measured withortho-phtalaldehyde, ATP by luminometry, changes in mitochondrial membrane potential with JC-1, and mitochondrial mass with 10-Nonyl-Acridine Orange. NRNP1, TEMPO, and 4-amino-TEMPO (25-150 μM) protected SH-SY5Y cells from 6-OHDA-induced viability loss; the protection was much higher for NRNP1 than for free nitroxides. NRNP1 were better antioxidantsin vitroand permeated better the model BBB than free nitroxides. Exposure to 6-OHDA decreased the GSH level after 1 h and increased it considerably after 24 h (apparently a compensatory overresponse); NRNPs and free nitroxides prevented this increase. NRNP1 and free nitroxides prevented the decrease in ATP level after 1 h and increased it after 24 h. 6-OHDA increased the intracellular ROS level and mitochondrial superoxide level. Studied antioxidants mostly decreased ROS and superoxide levels. 6-OHDA decreased the mitochondrial potential and mitochondrial mass; both effects were prevented by NRNP1 and nitroxides. These results suggest that the mitochondria are the main site of 6-OHDA-induced cellular damage and demonstrate a protective effect of NRNP1 in a cellular model of PD.

In this paper, the electron magnetic resonance (EMR) of Ni 47 Co 3 Mn 35.5 In 14.5 alloy in ribbon and powder form are investigated. The EMR spectra for ribbons were registered within the temperature ranges 4 K ⩽ T ⩽ 100 K and 140 K ⩽ T ⩽ 380 K and for powdered ribbon within the temperature range 140 K ⩽ T ⩽ 380 K. Additionally, the magnetic properties of ribbon were also studied by using vibrating sample magnetometer (VSM) in the temperature range of 85 K ⩽ T ⩽ 400 K. At high temperature, the EMR signal consist of a single, asymmetric line. The temperature dependence of the inverse integrated intensity exhibits a Curie–Weiss like behaviour and Curie temperature ( T C ) determined from VSM equals 333 K. Below T C for ribbon sample the low field microwave absorption (LFMA) line was observed. The EMR spectra recorded for the powder sample are of a different shape than those for the ribbon sample. The powdering causes an increase of the effective skin depth, and the high-temperature lines lose asymmetric character. The Curie temperature is shifted relative to Curie temperature determined for the ribbon sample, but the structural phase transition is preserved.

TEMPO-phosphate has been introduced as a phosphate analogue to study phosphate transport in erythrocytes. The nitroxide is reduced intracellularly upon entering the cells, the membrane transport being the rate-limiting step of the loss of ESR signal. The use of TEMPO-phosphate is convenient and avoids the hazard of radioactivity. We studied the inhibition of TEMPO-phosphate transport to human erythrocytes by various compounds. DIDS and SITS, inhibitors of Band 3, inhibited the TEMPO-phosphate transport. 1-cyano-4-hydroxycinnamic acid, inhibitor of monocarboxylate transporters, did not affect the permeation of TEMPO-phosphate. The transport of TEMPO-phosphate was inhibited by various polyphenols, especially curcumin, naringin, quercetin, luteolin and kaempferol. Interestingly, 3-bromopyruvic acid, an alkylating agent and potential anticancer agent, induced an apparent enhancement of TEMPO-phosphate transport into erythrocytes.

Ascorbic acid (AA) has been reported to be both pro-and antiglycating agent. In vitro, mainly proglycating effects of AA have been observed. We studied the glycation of bovine serum albumin (BSA) induced by AA in vitro. BSA glycation was accompanied by oxidative modifications, in agreement with the idea of glycoxidation. Glycation was inhibited by antioxidants including polyphenols and accelerated by 2,​2′-​azobis-​2-​methyl-​propanimidamide and superoxide dismutase. Nitroxides, known to oxidize AA, did not inhibit BSA glycation. A good correlation was observed between the steady-state level of the ascorbyl radical in BSA samples incubated with AA and additives and the extent of glycation. On this basis we propose that ascorbyl radical, in addition to further products of AA oxidation, may initiate protein glycation., Graphical abstract, Highlights • Ascorbic acid (AA) induced glycation of bovine serum albumin (BSA) in vitro. • Antioxidants, including polyphenols, inhibited glycation. • Nitroxides, known to oxidize AA, did not protect from glycation. • BSA glycation was accelerated by AAPH and superoxide dismutase. • Good correlation was found between the level of ascorbyl radical and extent of glycation. • We postulate that ascorbyl radical is able to induce protein glycation.

In this study, the electron magnetic resonance (EMR) spectra of annealed Ni 50 Mn 35.5 In 14.5 Heusler alloy ribbons within the temperature range 240 K ⩽ T ⩽ 360 K are investigated. In the paramagnetic region, the temperature dependence of the EMR linewidth is governed by the Korringa relaxation process. The g value exhibits a positive shift, which indicates a non-bottleneck regime. The temperature dependence of inverse integrated intensity exhibits a Curie-Weiss like behaviour with T C equals 298 K. The effects of annealing on the magnetic and structural ordering are discussed. Annealing increases the Curie temperature and changes the first-order phase transition temperature. Additionally, the low-field microwave absorption peak appears below the magnetic ordering temperature.

Studies of 54 antioxidants revealed that 27 of them, mainly polyphenols, generated hydrogen peroxide (H2O2) when added to Dulbecco's modified Eagle's medium (DMEM), other media used for culture of mammalian and yeast cells and phosphate-buffered saline. The most active antioxidants were: propyl gallate (PG), (-)-epigallocatechin gallate (EGCG) and quercetin (Q). Chelex treatment and iron chelators decreased H2O2 generation suggesting that transition metal ions catalyze antioxidant autoxidation and H2O2 production. Green tea also generated H2O2; tea prepared on tap water generated significantly more H2O2 than tea prepared on deionized water. Ascorbic acid decreased H2O2 production although it generated H2O2 itself, in the absence of other additives. Lemon added to the tea significantly reduced generation of H2O2. Hydrogen peroxide generated in the medium contributed to the cytotoxicity of PG, EGCG and Q to human prostate carcinoma DU-145 cells, since catalase increased the survival of the cells subjected to these compounds in vitro.

Magnetic properties of a Ni50Mn35.5In14.5 Heusler ribbon were studied by ferromagnetic resonance (FMR) in the temperature range of 335–100 K. In the temperature region of 265–170 K, the FMR signal disappeared, in spite of the fact that this region comprised the main crystal transformation temperatures: Ms , Mf , As , Af . In the austenite crystal state, a weak antiferromagnetic interaction was observed, whereas ferromagnetism was detected in the low temperature martensitic state.

In this work, the electron magnetic resonance (EMR) spectra of the mullites powders were measured for different grain sizes (0.07 and 0.12 mm). We have used EMR spectroscopy at X-band, combined with superposition model (SPM) calculations to reveal electronic structure and establish correlations between structure, and surroundings of these complexes. The main purpose of this work was to investigate the possible relationships between EMR spectra and the size of powder grains, as well as the identifi cation of EMR spectra in view of the potential application of EMR technique as a fi ngerprinting method [1, 2]. The motivation for this study comes from the need to solve the problem of fractures of shape and ceramic cores. Mullite is the only stable intermediate phase in the alumina-silica system at atmospheric pressure. The chemical formula for mullite is deceptively simple: 3Al2O3·2SiO2. However, the phase stability, crystallography, and stoichiometry of this material remain controversial. The structural variants are derived from the average structure considering crystal-chemical rules for bond lengths, atomic distances, and coordination number (Fig. 1) [3]. Considering these rules and different occupations of the Oc and Oc* sites, 34 structural variants result from the decomposition of the mullite average structure. Each four variants exhibit an oxygen vacancy on the same cell edge and different occupations of the Oc and Oc* sites on the remaining three edges. Structural variants 17 to 32 are vacancy free, but with a variation on the Oc/Oc* sites. Variants 33 and 34 represent the silica free i-Al2O3 modifi cation [3]. EMR study and superposition model analysis of Cr and Fe impurity ions in mullite powders used in aerospace industry Ireneusz Stefaniuk, Iwona Rogalska

The difficulty in determining the electron paramagnetic resonance (EPR) line parameters of ferromagnetic semiconductors has been addressed. For these materials, the resonance line is very broad and lies at low resonance field, so that only a part of the line can be detected experimentally. Moreover, the line is of asymmetric (Dysonian) shape as described by the line shape parameter α. We have compared values of line parameters derived by computer fitting of the whole experimental EPR line to the Dyson function (or modified Dyson function) with the values obtained by applying this procedure to the left and the right half of the line.

We have studied thin layers of Ni50-x Cox Mn50-y Iny alloys on (001) Si substrate obtained by pulsed laser deposition method (PLD) using YAG Nd3+ laser operating at second harmonic. The target was bulk Ni50-x Cox Mn50-y Iny (x = 5, y = 14.5) alloy prepared by induction melting of pure elements under argon atmosphere. Magnetic properties were investigated on Bruker X band EPR spectrometer (9.36 GHz) at room temperature. The magnetic resonance spectrum consists of non-symmetric lines with resonance field within wide field range (2500-4800 Gs) depending on the orientation of the static field in the plane perpendicular to the layer. Calculated spectroscopic splitting factor g = 2.09.

Temperature Electron Magnetic Resonance (EMR) measurements of multiwalled carbon nanotubes (CNT) and carbon nanohorns (CNH) were performed in the temperature range 5.2 – 300 K. The asymmetric resonance lines with Dyson shape were observed. The g-value of multiwalled carbon nanotubes (CNT) and carbon nanohorns (CNH) was calculated. Analysis of the temperature dependences of the integral intensity of EMR spectra was carried out using the Curie-Weiss law and Curie temperature θ(CNT) = 46,6 K and θ(CNT) = 8.6 K were obtained. We showed that the localization processes observed in nanocarbon materials lead to local quantum transport of spins or carriers.

In present work we were analysing thin layers of Ni-Co-Mn-In alloys, grown by pulsed laser deposition method (PLD) on Si, NaCl and glass substrates. For target ablation the second harmonics of YAG:Nd 3+ laser was used. The target had the composition Ni 45 Co 5 Mn 34.5 In 14.5 . The morphology of the layers and composition were studied by electron microscopy TESCAN Vega3 equipped with microanalyzer EDS – Easy EdX system working with Esprit Bruker software. The X-ray diffraction measurements (XRD), performed on spectrometer Bruker XRD D8 Advance system, reveals Ni 2 -Mn-In cubic phase having lattice constant a = 6.02A.

We report a study of the Pb 1− x Mn x I 2 bulk crystals and nanocrystals using electron paramagnetic resonance (EPR). The samples of the bulk Pb 1− x Mn x I 2 crystals with x in the range from 0 to 0.05 have been grown by Bridgman technique. The composite nanostructures containing the diluted magnetic semiconductor nanocrystals of Pb 1− x Mn x I 2 with x in the range from 0 to 0.15 have been prepared by embedding them into gelatin and polyvinylalcohol matrices using colloidal technology. The EPR spectra consist of an intense broad line and several weak narrow lines which correspond to hyperfine spectra of Mn 2+ ions. The temperature dependence of EPR spectra suggests of strong spin exchange interactions due to presence of magnetic ions in the bulk crystals and nanoparticles. The good agreement temperature dependence of integral intensity of Mn 2+ ions for bulk crystals and nanocrystals with the Curie–Weiss law was obtained.

The electron paramagnetic resonance (EPR) measurements of PbMoO4 single crystals doped with Co2+ ions (0.5 wt.%) carried out at temperature range 10–12 K are reported. The observed spectra reveal evidently two major groups of EPR spectra, each group consists of eight hyperfine structure components associated with the Co nuclear spin I = 7/2. Additionally, EPR spectra of the unintentional impurities have been observed, which have been assigned to Nd3+ ions in PbMoO4. The analysis of the various characteristic features of the EPR spectra as well as our earlier optical absorption studies of Co2+:PbMoO4 indicate that the Co2+ ions are located at two crystallographically distinct complexes, denoted Co2+(α) and Co2+(β). The fictitious ‘spin’ S′ = ½ has been assigned to the observed ground Kramers doublet state of each of the two Co2+ complexes tentatively identified as located at the Mo sites in PbMoO4. The spin Hamiltonian parameters for Co2+ (S′ = ½) ions in PbMoO4, including the components of the Zeeman and hyperfine structure tensors gij and Aij, respectively, are experimentally determined for the first time. Comparison of our results with the values of gij and Aij for Co2+ ions in other structurally similar compounds further strengthens this conclusion. Correlation of the present results with those obtained earlier from optical studies is discussed. Alternative assignments of the ground states and options for the origin of the ‘spin’ S′ = ½ for Co2+ ions in PbMoO4 will be considered in a subsequent paper.

The aim of this study was to investigate the oxidation of selected vegetable oils (CLSO, CCSO, CBO) at accelerated oxidation rates. Several seldom used analytical methods were applied including electron paramagnetic resonance (EPR), spin trapping with α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), Fe2+-induced chemiluminescence, Rancimat tests, and the determination of conjugated diens at λ = 233 nm. The antioxidative properties of POBN and DMPO were also investigated. The time required for each method was determined. EPR spectrometry of trapped radicals generated during oxidation turned out to be the fastest method to determine oxidative stability. Chemiluminometric determination of oxidation kinetics showed that POBN has a very strong anti-oxidative potential: it significantly (by 160–277%) lengthened the time to the chemiluminescence peak, as well as the induction time in the Rancimat test (by 110–140%). Photo-oxidation studies showed that superoxide anion radicals are the main factor responsible for the oxidation of lipids in the investigated oils.

In this paper, we report electron paramagnetic resonance (EPR) measurements of YAlO3 (YAP) single crystals and their preliminary theoretical analysis. Two kinds of the as-grown and annealed (in reducing N2 plus H2 atmosphere at 1100 K) YAP samples, nominally pure and doped with Co2+ ions, were studied. The presence of small amounts of Cr3+ and Fe3+ paramagnetic centers is revealed from the observed EPR spectral lines. In the annealed crystals, a decrease in the line intensity for Fe3+ ions and a simultaneous increase for Cr3+ ions is observed. Interestingly, a gradual decrease in intensity of both the Cr3+ and Fe3+ lines down to zero has been observed in EPR spectra below 80 K. The aim of this paper, first in the series of investigations, is to unravel characteristics of unintentional impurities present in nominally pure YAP crystals as indicated by EPR measurements. For this purpose, the spin Hamiltonian analysis of EPR spectra has been carried out on the basis of the triclinic (C i ) site symmetry. The fitted spin Hamiltonian parameters for Cr3+ and Fe3+ ions, i.e., zero-field splitting parameters and the Zeeman electronic tensor components, agree well with literature data. More detailed analysis of low symmetry aspects involved in EPR studies based on superposition model will be provided elsewhere.

In the present work, a CdTe alloy doped with a relatively high concentration of chromium (1%), and a CdTe:Cr layer, have been studied. Absorption and reflectivity spectra were measured at room temperature. They indicate the presence of chromium in the divalent state, both in the alloy and in the layer.

Pentacene have recently become the subject of intense studies due to their physical properties which follow from the states of their outer-shell electrons that are able to take part in molecule bonding. The symmetry of these molecules provides the classification of quantum states according to the group theory method. In this paper, we apply a molecular state-space factorization scheme for the classification of pentacene molecules based on the structure of their electron states.

Two-dimensional (2D) materials such as GaSe, InSe, and WSe2 in form of bulk crystal and few-layer sheets have been prepared by mechanical exfoliation method. Atomic force microscopy (AFM) analysis was used for the study of surface morphology and estimation of thicknesses of the exfoliated thin semiconductor layers. Optical absorption and magneto-optical Faraday rotation spectra of 2D materials at different temperatures have been studied. In spectral region near long-wavelength absorption edge for all the studied layered crystals at low temperatures the exciton series have been observed. It was shown that in GaSe and InSe crystals these series consist of three lines, whereas in WSe2 two exciton lines were revealed. The observed exciton series were interpreted in framework of 3D exciton model. In the absorption spectra of GaSe and InSe crystals at higher photon energies than band gap Eg additional exciton structure also was observed. In case of thin exfoliated WSe2 flakes with thickness less than 80 nm shift of ground exciton band to shorter wavelengths has been revealed, which is associated with quantum size effect. Faraday rotation spectra of the 2D crystals have been confirme INTRODd dominant role of excitons near absorption edge.

The results of X-band electron paramagnetic resonance (EPR) measurements of Co2+ ions in YAlO3 (YAP) crystals in the temperature range 1.8?40?K are presented. The temperature and angular dependences of EPR spectra have been analysed using a triclinic spin Hamiltonian (SH) consisting of the electronic Zeeman and hyperfine terms. Two distinct positions ? and ? are identified for Co2+ complexes and ascribed to the substitutional Co2+ ions at the Al3+ and Y3+ sites, respectively. The values of the SH parameters are obtained by least squares fitting the ?-?and ?-type Co2+ spectra yielding the principal (orthorhombic-like) values of the tensors g and A as well as the orientation of their principal axes. The additionally observed EPR spectra of the unintentional impurities Nd3+ and Er3+ in YAP crystals are also analysed.