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On the basis of the higher order perturbation formulas of g factors for a 4d1 group in tetragonally compressed octahedra, the g factors, optical absorption, local structure, and their concentration dependences of pentavalent molybdenum in 40PbO-(10 - x)Y2O3-50P2O5:xMoO3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter Dq, covalent factor N, and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8% to 4.2%. The decreasing trend of Dq and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO3 and Y2O3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo5+, associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems. [ABSTRACT FROM AUTHOR]

The k0 values of 6 non-1/v nuclides (152Eu, 152mEu, 154Eu, 177Lu, 192Ir and 194Ir) were determined using the extended Høgdahl formalism at the research reactor FRM II with very high f values. Standards were irradiated in 4 channels at different local temperatures between 40 °C and 55 °C measured using temperature sensitive irreversible labels. A good agreement with the recommended values was found for 152Eu, 154Eu and 177Lu using the original g(Tn) factors by Gryntakis, however, the k0 values for 152mEu in this work were 7% higher. New k0 values were also determined using the g(Tn) factors by Van Sluijs. Differences up to 6% were found for Eu isotopes compared with the recommended values. The recommended k0 values for 192Ir and 194Ir could be confirmed using g = 1. The theoretical k0 values for 177Lu were calculated using new nuclear data. They are up to 6% less than the recommended values. The present k0 values determined in this work showed a similar trend. The influence of different g(Tn) factors on the determination of the k0 values was investigated. [ABSTRACT FROM AUTHOR]

The neutron temperature at different irradiation positions in the research reactor FRM II was measured using thermometer labels together with lutetium standards. This was the first time to measure the local temperature at the irradiation positions with this combination. The simplified Westcott formalism was used to calculate the neutron temperature using Lu and g(Tn) factors from different data sources. The results showed agreement between neutron temperature according to the Lu method and the temperature showed on the labels. They can be used as a reliable alternative to determine the neutron temperature instead of using Lu standards in the extended k0 NAA. [ABSTRACT FROM AUTHOR]

Environmentally persistent free radicals (EPFRs) were previously considered an unrecognized composition of air pollutants and might help explain the long-standing medical mystery of why non-smokers develop tobacco-related diseases such as lung cancer. However, there is no investigated on EPFRs in Xuanwei rural areas, especially in high prevalence of lung cancer areas. In this study, we selected six types of coal and three types of biomass in Xuanwei, then conducted simulated combustion, and six group of atmospheric particulate matters (APMs) to explore the content and particle size distribution pattern of EPFRs and a new health risk assessment method to evaluate the risk of EPFRs in PM for adults and children. Our results show that the contribution of EPFRs for biomass combustion, coal combustion and APMs were mainly distributed in the size range of 3.3. Our results provides a new perspective and evidence for revealing the reason for the high incidence of lung cancer in Xuanwei, China.

The EPR g factors g// and g⊥ for the tetragonal (CrO4)3− impurity center in ZrSiO4: Cr5+ crystal are studied from the high-order perturbation formulas based on the two-mechanism (the crystal field and charge-transfer mechanisms) model. The studies indicate that differing from the tetragonally-elongated host (SiO4)4- tetrahedron, the dominant defect structure of the substitutional (CrO4)3− tetrahedron is tetragonally- compressed with the ground state |dz2 due to the Jahn-Teller distortion. Furthermore, the agreement of g factors between calculation and experiment requires a small admixture of the first excited state |dx2−y2 to the ground state |dz2 due to the vibrational motion of ligands, which leads a compressed (CrO4)3− tetrahedron to become a twinkling elongated one, These results are discussed. [ABSTRACT FROM AUTHOR]

Several Ce 3+ centers were experimentally found in Ce 3+ -doped potassium magnesium fluoride (KMgF 3 ) crystal by electron-spin resonance (ESR) spectra, but there was no definite conclusion about the charge-compensating mechanism. In the present work, we carried out a comprehensive investigation on local structures around Ce 3+ centers in the host, based on a combination of first-principles calculations and phenomenological analyses. The site occupation preference, crystal-field energy levels and spectral parameters ( e.g. crystal-field parameters, and g factors) for Ce 3+ ions in the host were derived, which are compatible with previously measured excitation and ESR spectra. Accordingly, four Ce 3+ centers (at K + sites) observed in ESR spectra are assigned successfully. In particular, the Ce 3+ center previously thought to be associated with a Mg 2+ site is reassigned to a K + site, in agreement with the results of defect formation energy calculations. The presented calculations together with optical and ESR spectroscopy techniques may offer cross check for reliable determination of impurity sites in luminescent materials. [ABSTRACT FROM AUTHOR]

The first-excited state g factor of 26 Mg has been measured relative to the g factor of the Mg 24 ( 2 1 + ) state using the high-velocity transient-field technique, giving g = + 0.86 ± 0.10 . This new measurement is in strong disagreement with the currently adopted value, but in agreement with the sd -shell model using the USDB interaction. The newly measured g factor, along with E ( 2 1 + ) and B ( E 2 ) systematics, signal the closure of the ν d 5 / 2 subshell at N = 14 . The possibility that precise g -factor measurements may indicate the onset of neutron pf admixtures in first-excited state even–even magnesium isotopes below 32 Mg is discussed and the importance of precise excited-state g -factor measurements on sd shell nuclei with N ≠ Z to test shell-model wavefunctions is noted. [ABSTRACT FROM AUTHOR]

This study concerns the equilibrium geometric properties of a family of cyclic chains, referred to as the 'bridged polycyclic rings,' which have f flexible subchains bridging two common branch points. By increasing the number of bridges, f, this family encompasses the usual linear chain ( f = 1), monocyclic ring ( f = 2), bicyclic θ-shaped polymer ( f = 3), and multicyclic rings with increasing topological complexity. Results of their radius of gyration, mean span, and, consequently, geometric shrinking factors (also known as the g-factors) are obtained by three approaches-the Gaussian chain theory, simulations based on the Kremer-Grest bead-spring model, and a Flory-type mean-field approach. Using the confinement analysis from bulk structures method, the equilibrium partition coefficients ( K) of several of those cyclic excluded volume chains in a cylindrical pore with inert surfaces are obtained, and the results fall onto a common curve on a graph of K versus the polymer-to-pore size ratio, using the mean span as the representative polymer size, in the range of K relevant to polymer separation in size exclusion chromatography (SEC) experiments. Applications of the results in predicting the SEC retention volume of such bridged polycyclic ring polymers are discussed in the framework of the equilibrium partition theory. [ABSTRACT FROM AUTHOR]

One-dimensional ballistic transport is demonstrated for a high-mobility InAs nanowire device. Unlike conventional quantum point contacts (QPCs) created in a two-dimensional electron gas, the nanowire QPCs represent one-dimensional constrictions formed inside a quasi-one-dimensional conductor. For each QPC, the local subband occupation can be controlled individually between zero and up to six degenerate modes. At large out-of-plane magnetic fields Landau quantization and Zeeman splitting emerge and comprehensive voltage bias spectroscopy is performed. Confinement-induced quenching of the orbital motion gives rise to significantly modified subband-dependent Landé g factors. A pronounced g factor enhancement related to Coulomb exchange interaction is reported. Many-body effects of that kind also manifest in the observation of the 0.7·2e2/h conductance anomaly, commonly found in planar devices. [ABSTRACT FROM AUTHOR]

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Highlights: [•] We study g factors and Knight shifts for Y123 and Y124 superconductors. [•] The theoretical relationships between Knight shifts and g factors are established. [•] High order perturbation formulas are adopted with local structures of Cu2+ sites. [•] Anisotropies of g factors and Knight shifts are ascribed to elongation of Cu2+ sites. [ABSTRACT FROM AUTHOR]

Abstract: The EPR g factors g // and g ⊥ for the tetragonal Ce3+ centers in AWO4 (A=Ca, Sr, Pb) and A′MoO4 (A′=Sr, Pb) crystals with scheelite-type structure are calculated in terms of the complete diagonalization (of energy matrix) method. In the matrix, the crystal field parameters B kq are estimated from the superposition model where the intrinsic parameters are taken as those obtained in very similar (CeO8)13− clusters in MPO4 (M=Y, Lu) crystals. The calculated g-values are in reasonable agreement with the experimental data when both covalence of the rare earth ion clusters, reflected in the presence of an orbit reduction factor k<1, and the local deformation due to the difference between the Ce3+ and host lattice cation radii are considered. [Copyright &y& Elsevier]

Abstract: The g factors g ∥ and g ⊥ for the tetragonally-compressed (CrO4)3− clusters in YMO4 (M=V, P) crystals are calculated from the high-order perturbation formulas based on the two-mechanism model for the compressed d1 tetrahedra with the ground state |d z 2 〉. From the calculated values and by considering a small admixture of the first excited state |d x 2 −y 2 〉 to the ground state |d z 2 〉 due to the vibrational motion of ligands (which leads a twinkling compressed tetrahedron to become an elongated one), the observed g ∥ and g ⊥ for Cr5+ centers in YMO4 crystals are explained reasonably. The difficulty of the large deviations of g ∥ from g e (≈2.0023) in the two systems is therefore removed and the above dynamic effect may be the cause which results in the large deviation of g ∥ from g e for some (CrO4)3− clusters in crystals. [Copyright &y& Elsevier]

Abstract: The exchange charge model of crystal field was used to calculate the crystal filed parameters (CFPs) acting upon the V2+ electrons in the Al2O3 crystals. With those CFPs, the crystal field Hamiltonian was diagonalized in the complete space spanned by all wave functions of the 3d3 electron configuration of divalent vanadium. The obtained wave functions of the calculated energy levels were used to estimate the zero filed splitting (ZFS) of the ground state and g factors of ground and the first excited states for V2+ ion in Al2O3 crystals. The theoretical results are in good agreement with the corresponding experimental data. Numerical estimations of the contributions to the ZFS and g factors arising from the nearest ligands and ions from further coordination spheres were performed. It has been shown that consideration of a large cluster around an impurity ion leads to improvement of the calculated results. [Copyright &y& Elsevier]

The electron paramagnetic resonance (EPR) g-factor formulas are constructed for ZnSe:Ti2+, CdTe:Ti2+ and ZnSe:V3+ crystals based on the contributions of the charge-transfer levels and the spin-orbit coupling effect of the central ion and the ligands. The EPR g factors are calculated from these formulas, and the calculated values agree well with the experimental ones. The contribution rates of the charge-transfer levels are 10.1, 7.6 and 24.9% for ZnSe:Ti2+, CdTe:Ti2+ and ZnSe:V3+ crystals, respectively. The g factors obtained from the one-spin-orbit-parameter model are also given for comparison. [ABSTRACT FROM AUTHOR]

Abstract: By using complete diagonalization method, the zero-field splitting and g factors of the ground 4 A 2 and the first excited 2 E states of Cr3+ ions in emerald are calculated. The theoretical results are in good agreement with the experimental data. The dependencies of the g factors on the crystal field parameters, including Dq, v, and , have been studied. It is shown that, the g factors of the ground state varied with the crystal field parameters approximately in a linear way, but the g factors of the first excited state varied nonlinearly with these parameters. [Copyright &y& Elsevier]

Experiments in ion traps on the g factors for the free and the bound electron in low- Z, hydrogen-like ions have provided the most accurate tests of quantum-electrodynamics calculations. Moreover they have been used to determine new and precise values for fundamental constants. Extensions to more stringent tests using ions of higher values of the nuclear charge Z are on the way. Also other QED tests such as Lamb shifts or hyperfine structures in H-like ions using traps will be feasible in the near future. The tests in bound systems, however, will be limited by nuclear structure effects which are difficult to calculate. Assuming the QED calculations as correct, the experimental results may be used to determine nuclear contributions and thus support nuclear models. [ABSTRACT FROM AUTHOR]

Abstract: The electronic structure, electron and hole g factors and optical properties of CdTe quantum ellipsoids are investigated, in the framework of eight-band effective-mass approximation. It is found that the light-hole states come down in comparison with the heavy-hole states when the spheres are elongated, and become the lowest states of valence band. When the aspect ratio of the ellipsoid length to diameter changes from smaller than 1 to larger than 1, the linear polarization factors change from negative to positive. The electron g factors of CdTe spheres decrease with increasing radius, and are nearly 2 when the radius is very small. Actually, as some of the three dimensions increase, the electron g factors decrease. More dimensions increase, the g factors decrease more. The dimensions perpendicular to the direction of the magnetic field affect the g factors more than the other dimension. The light-hole and heavy-hole g factors of quantum spheres are equal, and change from to with increasing radius. When the light-hole g factor is smaller (larger) than the heavy-hole g factor. [Copyright &y& Elsevier]

Abstract: The g factors of the and states in radioactive 52Ti () have been measured for the first time using the technique of α transfer to 48Ca beams in inverse kinematics, in combination with transient magnetic fields. In addition, employing the Doppler-shift-attenuation method, the lifetime of the state has been re-determined with much higher precision while the lifetime values of the and the states were obtained for the first time. The and g factor results were compared with the results obtained within the framework of full fp spherical shell model calculations using several recent effective interactions commonly utilized in this mass region. The two measured g factors were accounted for by none of the calculations except for the FPD6 calculation with modified input single-particle energies. The new data were also discussed in relation to the neighbouring isotopes, 48,50Ti, isotones, 50,52,54Cr, and the magic shell closure. Our calculations generally reproduce well the trends of the data in terms of their dependence on neutron number. [Copyright &y& Elsevier]

Measurements of g factors and lifetimes of the 2+1 states in 36,38Ar have been performed via α-transfer reactions using 32S and 34S ions in inverse kinematics combined with the techniques of transient magnetic fields and Doppler-shift-attenuation. The variations, with the neutron number, of the measured g factors and values of 36,38,40Ar have been explained by large-scale shell model calculations. The good agreement achieved between experiment and theory demonstrates the impact of the effective nucleon–nucleon interactions and the magic N=20 shell closure. The present new results are a very good show-case for the universal difference in sensitivity of excitation energies, magnetic moments and electromagnetic transition probabilities to nuclear wave functions behaviour as closed shells are approached, crossed, and left behind. Aspects of the collectivity of these nuclei are also discussed from the perspective of a simple vibrational model. [Copyright &y& Elsevier]

Abstract: Transient-field strengths for Mg ions traversing Gd hosts have been measured above the K-shell electron velocity. The results support a recent model-based extrapolation of the transient-field strength and show sufficient magnitude for g-factor measurements on exotic nuclei near the island of inversion around 32Mg produced as intermediate-energy fragments. [Copyright &y& Elsevier]

On the basis of the higher order perturbation formulas of g factors for a 4d 1 group in tetragonally compressed octahedra, the g factors, optical absorption, local structure, and their concentration dependences of pentavalent molybdenum in 40PbO-(10 - x)Y 2 O 3 -50P 2 O 5 :xMoO 3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo 5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter D q , covalent factor N, and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8% to 4.2%. The decreasing trend of D q and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO 3 and Y 2 O 3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo 5+ , associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems., (© 2021 John Wiley & Sons, Ltd.)

Environmentally persistent free radicals (EPFRs) were previously considered an unrecognized composition of air pollutants and might help explain the long-standing medical mystery of why non-smokers develop tobacco-related diseases such as lung cancer. However, there is no investigated on EPFRs in Xuanwei rural areas, especially in high prevalence of lung cancer areas. In this study, we selected six types of coal and three types of biomass in Xuanwei, then conducted simulated combustion, and six group of atmospheric particulate matters (APMs) to explore the content and particle size distribution pattern of EPFRs and a new health risk assessment method to evaluate the risk of EPFRs in PM for adults and children. Our results show that the contribution of EPFRs for biomass combustion, coal combustion and APMs were mainly distributed in the size range of <1.1 μm, which accounted for 76.15 ± 4.14%, 74.85 ± 10.76%, and 75.23 ± 8.18% of PM3.3. The mean g factors and ΔHp-p indicated that the EPFRs were mainly oxygen-centered radicals in PM in Xuanwei. The results suggest that the health risk of EPFRs is significantly increased when the particle size distribution of EPFRs is taken into account, and coal combustion particulate matter (174.70 ± 37.86 cigarettes for an adult, 66.39 ± 14.39 cigarettes per person per year for a child) is more hazardous to humans than biomass combustion particulate matter (69.41 ± 4.83 cigarettes for an adult, 26.37 ± 1.84 cigarettes per person per year for), followed by APMs (102.88 ± 39.99 cigarettes for an adult, 39.10 ±15.20 cigarettes per person per year for) in PM3.3. Our results provides a new perspective and evidence for revealing the reason for the high incidence of lung cancer in Xuanwei, China. [ABSTRACT FROM AUTHOR]

Abstract: Taking into account the spin–spin (SS), spin-other-orbit (SOO), the orbit–orbit (OO) magnetic interactions besides spin–orbit (SO) interaction, the zero-field splitting (ZFS) of 2 E state and factors of (2 E) term for ions in crystal are studied in the intermediate-field coupling scheme using complete diagonalization method. It is shown that the ZFS of 2 E state and factors of (2 E) term arise from five microscopic mechanisms including SO coupling mechanism, SS coupling mechanism, SOO coupling mechanism, OO coupling mechanism, and SO–SS–SOO–OO combined coupling mechanism. The relative importance of the five contributions to the ZFS of 2 E state and factors of (2 E) term is investigated. [Copyright &y& Elsevier]

Abstract: We report on a theoretical study of Landég factors of electrons and holes in InAs/GaAs self-assembled quantum dots. We find that the g factor of holes in quantum dots can be easily tuned by changing the aspect ratio of the structures while the g factor of electrons exhibits relatively weak dependence on the geometry. The dependence of the g factor of holes on the elongation is attributed to the fact that the proportion of heavy- and light-hole components in the ground state of holes is sensitive to the geometry of the quantum dots. [Copyright &y& Elsevier]