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ab initio calculations of dielectronic recombination rate coefficient of W 37 + forming W 36 + and electron-impact ionization cross section of W 36 + have been performed. Energy levels, radiative transition probabilities, autoionization rates, electron-impact excitation and ionization cross sections are calculated using the flexible atomic code (FAC). Good agreement between the present level-to-level distorted wave treatment and previous ADAS data is found for the dielectronic recombination rate coefficients of W 37 + . Electron-impact direct ionization and excitation-autoionization contributions to the total single-ionization cross sections were calculated employing a level-to-level distorted-wave approximation. The calculation result shows that the total ionization cross section will be underestimated by 50% near ionization threshold to ∼ 8% at higher energy without include the contribution from excitation-autoionization process. [ABSTRACT FROM AUTHOR]

In this study, Ho3+-doped 0.825K0.5Na0.5NbO3-0.175Sr(Yb0.5Nb0.5)O3 luminescence transparent ceramics were prepared via the traditional solid-state sintering method. The structure and optical properties of the ceramics before and after polarization were studied at 40 kV cm−1 for 0.5 h. With the increase of Ho content, the phase structure of the ceramics changed from a pseudo-cubic phase to the tripartite and the orthorhombic phases, and the light transmittance decreased. The ceramics demonstrated an up-conversion luminescence characteristic under the excitation of a 980 nm laser, and the emission wavelengths were 550 and 670 nm. The best up-conversion luminescence performance was obtained when the Ho content was 0.1%. Moreover, the polarization markedly enhanced the luminescence performance of the 0.825K0.5Na0.5NbO3-0.175Sr(Yb0.5Nb0.5)O3-0.1%Ho ceramics due to the increased possibility of energy-level radiative transition of rare-earth Ho3+ ions and reduction of the Eg value of the ceramic. [ABSTRACT FROM AUTHOR]

Photoionization (PI) of the Ti9+ ion is investigated using the Dirac R-matrix method. Multi-configuration Dirac–Fock (MCDF) calculations are performed to construct accurate target functions. Good agreement of energy levels and radiative transition rates indicate the accuracy of target functions. PI cross sections show good consistency between length and velocity forms. The results are consistent with the previous theoretical values in high-energy regions. Partial waves' contribution to the total PI cross sections are discussed for the GS and MS. Moreover, the PI cross sections are dominated by many resonance structures and affected by the channel coupling effects in the low-energy region. In addition to providing data for the Opacity Project TOPbase, the present work promotes plasma simulation and diagnosis. [ABSTRACT FROM AUTHOR]

Luminescence thermometry has been extensively exploited in the last decades both from the fundamental and applied point of views. The application of photoluminescent nanoparticles on the microscopic level based on rare-earth doped (RED) nanostructures is yet a challenge. Distinct underlying physical mechanisms in the RED nanomaterials have been exploited, such as intensity ratio between radiative transitions associated with thermally coupled energy levels, energy peak and lifetime of an excited state variations with the temperature. The drawbacks of such systems are the relatively low thermal sensitivity (S r), and the large temperature uncertainty. To overcome that, several research groups have been seeking new functionalized materials. The majority of the efforts have been directed towards increasing S r with record around 10%°C−1, which is, however, considered unsatisfactory. We propose the use of an automated machine learning tool to retrieve an ideal pipeline improving the response of photoluminescence thermometers. As a proof-of-concept, we used Nd3+-doped YAG nanoparticles, excited at 760 nm, and the photoluminescence spectra in the range from 860 nm to 960 nm as input parameters. In addition to the improvement in the accuracy (> 5.5 × over traditional methods), the implementation is very simple, without the requirement of any deconvolution procedure or knowledge of any underlying physical mechanism. Our findings demonstrate that this approach is resilient to natural variances across various spectral acquisitions, which may otherwise lead to an inaccurate estimation of temperature, opening the door for real-time applications. Our open-source code is designed to be accessible to individuals without programming experience. [Display omitted] • Automated machine learning selects the best model. • Best model improves the accuracy of photoluminescent thermometers (5.5x). • Photoluminescence of neodymium ions was used as a proof-of-concept. • The proposal can be extended to any photoluminescent material. • An open-source code is available to individuals without programming experience. [ABSTRACT FROM AUTHOR]

The probabilities of the 4 f 135p66p + 4 f 145p56p – 4 f 136s, 4 f 137s radiative transitions and the lifetimes of the 4 f 137s levels in the spectrum of the erbium-like W VII ion are calculated in the electric dipole approximation by the semiempirical intermediate coupling method using experimental energy levels known from the literature. The radial integrals necessary for calculating the absolute transition probabilities are obtained in the form of length with the Hartree–Fock functions. [ABSTRACT FROM AUTHOR]

Sub-monolayer quantities of Mg are introduced in multilayer stacked ZnMgTe quantum dots (QDs) embedded in ZnSe barriers in order to reduce the hole confinement energy by controlling the bandgaps and band-offsets of ZnTe/ZnSe system having type-II band alignment. The photoluminescence (PL) emission from such ZnMgTe/ZnSe QD structure is found to be a broad band centered at 2.35 eV. The higher energy side of the PL band shows a larger blue-shift with increasing excitation intensity and a faster life-time decay due to a greater contribution of the emission from the smaller size dots and the isoelectronic bound excitons. It is found that the characteristic decay time of the PL evolves along the band with a value of 129 ns at 2.18 eV to 19 ns at 2.53 eV. The temperature dependent PL emission is controlled by two thermally activated processes: ionization of electrons away from QD state to the barrier (EA1 ∼ 3 meV) by breaking the type-II excitons and thermal escape of the holes from the ground state to the barrier (EA2 ∼ 114-116 meV). We propose a modified band diagram and energy levels for this ZnMgTe/ZnSe multilayer QD system by determining the composition of Mg inside the QDs and solving the 1-D Schrodinger's equation and show that Mg incorporation lowers the hole activation energy via modification of the valence band offset without changing the barrier significantly. [ABSTRACT FROM AUTHOR]

Using fully relativistic multiconfiguration Dirac-Fock (MCDF) wavefunctions in the active space approximation, the energy levels, lifetimes, radiative rates, and oscillator strengths are determined for transitions in Mn-like W L ion. For the calculations, Breit interaction (BI) and quantum electrodynamics (QED) corrections to the levels are estimated in extensive relativistic configuration interaction (RCI) procedure, and results are reported for all electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions among the lowest 121 levels, belonging to the 3 s 2 3 p 6 3 d 7 , 3 s 2 3 p 5 3 d 8 , 3s3 p 6 3 d 8 , 3 s 2 3 p 4 3 d 9 , and 3s3 p 5 3 d 9 configurations. Comparisons are made with similar data obtained with FAC (Flexible Atomic Code) to assess the accuracy of the results. The present results are also assessed by comparison with the data compiled by the Atomic Spectra Database (ASD) of National Institute of Standards and Technology (NIST) and other existing theoretical/experimental ones for few levels in literature showing an overall good agreement. i.e., the energies agree within 0.5% with the experimental results, and the M1 transition rates agree within 5% with other theoretical results. Beside the ground configuration, almost all atomic parameters presented in this work are calculated for the first time and thus significantly increases the amount of accurate data for W L ion. Our results should be beneficial in future for identification of spectral lines, in plasma modelling, and in fusion plasma research. [ABSTRACT FROM AUTHOR]

A systematic analysis of the S1-trans (A1Au) state of acetylene, using IR-UV double resonance along with one-photon fluorescence excitation spectra, has allowed assignment of at least part of every single vibrational state or polyad up to a vibrational energy of 4200 cm-1. Four observed vibrational levels remain unassigned, for which no place can be found in the level structure of the trans-well. The most prominent of these lies at 46 175 cm-1. Its 13C isotope shift, exceptionally long radiative lifetime, unexpected rotational selection rules, and lack of significant Zeeman effect, combined with the fact that no other singlet electronic states are expected at this energy, indicate that it is a vibrational level of the S1-cis isomer (A1A2). Guided by ab initio calculations [J. H. Baraban, A. R. Beck, A. H. Steeves, J. F. Stanton, and R. W. Field, J. Chem. Phys. 134, 244311 (2011)] of the cis-well vibrational frequencies, the vibrational assignments of these four levels can be established from their vibrational symmetries together with the 13C isotope shift of the 46 175 cm-1 level (assigned here as cis-3161). The S1-cis zero-point level is deduced to lie near 44 900 cm-1, and the ν6 vibrational frequency of the S1-cis well is found to be roughly 565 cm-1; these values are in remarkably good agreement with the results of recent ab initio calculations. The 46 175 cm-1 vibrational level is found to have a 3.9 cm-1 staggering of its K-rotational structure as a result of quantum mechanical tunneling through the isomerization barrier. Such tunneling does not give rise to ammonia-type inversion doubling, because the cis and trans isomers are not equivalent; instead the odd-K rotational levels of a given vibrational level are systematically shifted relative to the even-K rotational levels, leading to a staggering of the K-structure. These various observations represent the first definite assignment of an isomer of acetylene that was previously thought to be unobservable, as well as the first high resolution spectroscopic results describing cis-trans isomerization. [ABSTRACT FROM AUTHOR]

We have studied the dynamics of strong radiative shocks generated with the high-energy subnanosecond iodine laser at Prague Asterix Laser System facility (Prague) over long time scales, up to 100 ns. These shock waves are characterized by a developed radiative precursor, a radiation driven ionization wave in front of the density jump of the shock. Electronic density profiles are measured at different times after the laser pulse and at different distances from the axis of the shock tube. A new feature, described as a split precursor, has been observed. Comparisons with two-dimensional computations are shown. [ABSTRACT FROM AUTHOR]

We present a nonperturbative time-dependent quantum mechanical theory of the laser catalysis and control of a bifurcating A+BC↔hω0ABC*(v)↔hω0AB+C reaction, with ABC*(v) denoting an intermediate, electronically excited, complex of ABC in the vth vibrational state. We apply this theory to the low collision energy fermion-boson light-induced exchange reaction, 6Li(2S)+7Li2(3Σu+)↔hω0(6Li7Li7Li)*↔hω06Li7Li(3Σ+)+7Li(2S). We show that at very low collision energies and energetically narrow (∼0.01 cm-1) initial reactant wave packets, it is possible to tune the yield of the exchange reaction from 0 to near-unity (yield >=99%) values. Controllability is somewhat reduced at collisions involving energetically wider (∼1 cm-1) initial reactant wave packets. At these energetic bandwidths, the radiative reactive control, although still impressive, is limited to the 0%–76% reactive-probabilities range. [ABSTRACT FROM AUTHOR]

The random first-order transition theory of the dynamics of supercooled liquids is extended to treat aging phenomena in nonequilibrium structural glasses. A reformulation of the idea of “entropic droplets” in terms of libraries of local energy landscapes is introduced which treats in a uniform way the supercooled liquid (reproducing earlier results) and glassy regimes. The resulting microscopic theory of aging makes contact with the Nayaranaswamy-Moynihan-Tool nonlinear relaxation formalism and the Hodge-Scherer extrapolation of the Adam-Gibbs formula, but deviations from both approaches are predicted and shown to be consistent with experiment. The nonlinearity of glassy relaxation is shown to quantitatively correlate with liquid fragility. The residual non-Arrhenius temperature dependence of relaxation observed in quenched glasses is explained. The broadening of relaxation spectra in the nonequilibrium glass with decreasing temperature is quantitatively predicted. The theory leads to the prediction of spatially fluctuating fictive temperatures in the long-aged glassy state, which have non-Gaussian statistics. This can give rise to “ultraslow” relaxations in systems after deep quenches. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A spectroscopic analysis is performed on Er[sup 3+] (4f[sup 11]) ions doped in NaBi(WO[sub 4])[sub 2] (NBWO) in order to assess this material for its potential as a near-infrared laser. The Judd–Ofelt model is applied to the room-temperature absorption intensities of Er[sup 3+] (4f[sup 11]) in NBWO to obtain the three phenomenological intensity parameters: Ω[sub 2]=5.50×10[sup -20] cm[sup 2], Ω[sub 4]=1.00×10[sup -20] cm[sup 2], and Ω[sub 6]=0.71×10[sup -20] cm[sup 2]. The intensity parameters are then used to determine the radiative decay rates (emission probabilities), radiative lifetimes, and branching ratios for the Er[sup 3+] transitions from the excited state multiplet manifolds to the lower lying manifold states. Using the radiative decay rates for the Er[sup 3+] (4f[sup 11]) transitions between the corresponding excited states and the lower lying states, the radiative lifetimes of eight excited states of Er[sup 3+] are determined in this host. Using the measured room temperature fluorescence lifetime of approximately 4.75 ms and the radiative lifetime of 5.63 ms as predicted by the Judd–Ofelt model for the [sup 4]I[sub 13/2]→[sup 4]I[sub 15/2] (1.52 μm) transition of Er[sup 3+] in NBWO the quantum efficiency is determined to be approximately 84% for this laser material. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Highlights • Potential energy curves of 13 electronic states for PN are calculated. • Spectral ranges and transition parameters for 15 dipole-allowed transitions are presented. • Theoretically strong emissions are provided for guiding experimental detections. • The emissions of the 23Δ-b3Π system are weak. • Radiative lifetimes of eight excited states are evaluated. Abstract The valence internally contracted multireference configuration-interaction (icMRCI) method is used to compute potential energy curves (PECs) of the X1Σ+, A1Π, C1Σ−, D1Δ, 21Π, a3Σ+, b3Π, d3Δ, e3Σ−, 23Δ, 23Σ−, 15Σ+ and 15Π states for PN, together with the Davidson, core-valence (CV) and scalar relativistic corrections, as well as the basis-set extrapolation. Transition dipole moments (TDMs) of fifteen dipole-allowed transitions between the thirteen states are calculated by the icMRCI approach with the aug-cc-pV6Z basis set. The vibrational band origins, Einstein coefficients and Franck-Condon factors of all spontaneous emissions for the fifteen band systems are determined, seeking to theoretically predict the strong emissions at least of the order of 103 s−1 for Einstein coefficients. Comparing with experimental measurements, our calculations can well reproduce the band origins and Franck-Condon factors of the A1Π-X1Σ+ system. Similar accuracy is assumed for the other band systems. Many emissions for the A1Π-X1Σ+, 21Π-A1Π, 21Π-X1Σ+, 21Π-C1Σ−, 21Π-D1Δ, b3Π-a3Σ+, e3Σ−-b3Π, 23Δ-13Δ, 23Σ−-13Σ−, 23Σ−-b3Π and 15Π-15Σ+ systems are found to be strong according to our calculated Einstein coefficients, whereas the emissions are weak for the 23Δ-b3Π system. Radiative lifetimes for the first 15 vibrational levels are evaluated to be about tens of nanoseconds for the 21Π state, about several hundred nanoseconds for the A1Π state, about several to tens of microseconds for the b3Π, 23Δ, 23Σ− and 15Π states and about several to several hundred microseconds for the e3Σ− state. The results can be used as guidelines for line identification and diagnostics of astrophysical plasma. [ABSTRACT FROM AUTHOR]

Highlights • High resolution VUV spectrum of tin excited in a vacuum spark was studied. • Transitions 4d75p- 4d75d in Sn VII are identified. • New 4d75d energy levels are derived from identified Sn VII wavelengths. • Parametric calculations are made for interpretation of Sn VII spectrum. • Transition probabilities are calculated for Sn VII lines in the region 153–1250 Å. Abstract The spectrum of tin excited in a vacuum spark was observed with a 6.6-m normal incidence spectrograph. The 4d75p – 4d75d transitions in Sn VII were studied. 137 spectral lines of these transitions in the region 556 - 763 Å were identified and 79 levels of the 4d75d configuration were found. Parametric calculations of the electric dipole transitions between the levels of the 4d8, 4p54d9, 4d75s, 4d76s, 4d75p and 4d75d configurations spanning the wavelength region from 153 Å through 1250 Å were performed. [ABSTRACT FROM AUTHOR]

Describes the measurements of x-ray power, spatial and spectral distributions from transition radiators whose spectra are narrowed by the foil material's K-shell photoabsorption edge. Peak and total power density of the zinc radiator; Discussion on how transition radiation is produced; Factors that determine the energy of the x-rays.

We tabulate spontaneous emission rates for all possible 811 electric-dipole-allowed transitions between the 75 lowest-energy states of Ca I. These involve the 4s n s ( n = 4 –8), 4s n p ( n = 4 –7), 4s n d ( n = 3 –6), 4s n f ( n = 4 –6), 3 d 2 , 4 p 2 , 3d4p, and 4s5g electronic configurations. We compile the transition rates by carrying out ab initio relativistic calculations using the combined method of configuration interaction and many-body perturbation theory. The results are compared to the available literature values. The tabulated rates can be useful in various applications, such as optimizing laser cooling in magneto-optical traps, estimating various systematic effects in optical clocks and evaluating static or dynamic polarizabilities and long-range atom–atom interaction coefficients and related atomic properties. [ABSTRACT FROM AUTHOR]

Calculations of energy levels, radiative data and lifetimes are reported for tungsten Ca-like ion (W LV) by using multi-configuration Dirac–Fock (MCDF) method. The GRASP2K package is adopted to carry out a large-scale systematic computation with a restricted active space treatment; the Breit interaction and QED effects are included in subsequent relativistic configuration interaction calculations. The energies and lifetimes of the lowest 119 levels are listed; the main leading configuration of the levels is of the ground state configuration [Ne]3s 2 3p 6 3d 2 and the first excited configuration [Ne]3s 2 3p 5 3d 3 . The wavelengths, radiative rates and oscillator strengths for relatively strong E1, E2, M1, and M2 transitions are listed. Comparisons with earlier experimental and theoretical values are made. The average relative deviations of energy levels from the NIST results and E1 transition wavelengths from the EBIT experimental results have turned to be only 0.20% and 0.13%, respectively. The other present results are in reasonable agreement with available data. These agreements confirm the reliability and accuracy of the current results. The present datasets may help us with the investigation of the electron–electron correlation effects in complex multi-electron highly charged heavy ions and of the diagnosis of tungsten impurity plasmas in fusion science. [ABSTRACT FROM AUTHOR]

Considering the quantum effects of diffraction and the collective screening effects, the potential of test charge in semiclassical plasmas is derived. It is generalized exponential screened Coulomb potential. Using the Ritz variational method incorporating this potential, the effects of semiclassical plasma on the energy levels and radiative transitions are investigated systematically, taking highly charged H-like ion as an example. The Debye plasma model is also employed for comparison purposes. Comparisons and analysis are made between these two sets of results and the differences are discussed. Graphical abstract: [ABSTRACT FROM AUTHOR]

In this Comment I discuss two incorrect statements which were made in the paper “Silver nanoparticle array structures that produce remarkably narrow plasmon line shapes” [J. Chem. Phys.130, 10871 (2004)] by Zou, Janel, and Schatz (ZJS). The first statement is about the use of quasistatic approximation in my earlier work on the similar subject, and the second statement concerns the possibility of exact cancellation of radiative relaxation in periodical chains of nanoparticles. The relationship between the quasistatic approximation, the dipole approximation, and the approximation due to Doyle [Phys. Rev. B39, 9852 (1989)] which was used by ZJS is clarified. It is shown that the exact cancellation of radiative relaxation cannot take place in the particular geometry considered by ZJS. [ABSTRACT FROM AUTHOR]

Hydrogen-like ions with high Z present unique opportunities to promote the understanding of atomic structure. On the other hand, determining the atomic structure of hydrogen-like atoms provides us the test of relativistic effects as well as accurate values of the spectral characteristics required for many applications. For this reason we have calculated level energies of hydrogen like thorium (Th89+, Z = 90) with both multiconfiguration Hartree-Fock (MCHF) and multiconfiguration Dirac-Fock (MCDF) methods. These calculations have contained the Breit-Pauli relativistic corrections in MCHF calculation and quantum electrodynamics effects in MCDF calculations besides electron correlations. The wavelengths, λ, weighted oscillator strengths, gf-value, and transition probabilities, Aki, have been also represented for allowed (E1) and forbidden (E2 and M1) transitions. We have compared our results with only theoretical work results because there is no available experimental data for Th89+. [ABSTRACT FROM AUTHOR]

The new emission spectrum of atomic argon is measured using the time-resolved Fourier transform technique. Seventy-seven new Ar I lines in the 800 – 2000 cm − 1 range with a resolution of 0.02 cm − 1 are observed. The energies of 12 previously unknown 7 i and 6 h energy levels are extracted from the measured spectra. The probabilities of the transitions between the observed levels are calculated. [ABSTRACT FROM AUTHOR]

Calculations of energy levels, radiative rates and lifetimes are reported for eight ions of tungsten, i.e. S-like (W LIX) to F-like (W LXVI). A large number of levels have been considered for each ion and extensive configuration interaction has been included among a range of configurations. For the calculations, the general-purpose relativistic atomic structure package ( grasp ) has been adopted, and radiative rates (as well as oscillator strengths and line strengths) are listed for all E1, E2, M1, and M2 transitions of the ions. Comparisons have been made with earlier available experimental and theoretical energies, although these are limited to only a few levels for most ions. Therefore for additional accuracy assessments, particularly for energy levels, analogous calculations have been performed with the flexible atomic code ( fac ). [ABSTRACT FROM AUTHOR]

Energy levels and radiative rates ( A -values) for transitions in Cr-like Cu VI and Zn VII are reported. These data are determined in the quasi-relativistic approach (QR), by employing a very large configuration interaction (CI) expansion which is highly important for these ions. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST and other available theoretical data, for a majority of the levels. The A -values (and resultant lifetimes) are listed for all significantly contributing E1, E2 and M1 radiative transitions among the energetically lowest 322 levels of each ion. [ABSTRACT FROM AUTHOR]

• Complete datasets of excitation energies, g factors, E1, E2, M1 radiative transition properties arising from the lowest 30 energy levels of Th3+ are determined by the relativistic coupled-cluster method. • Electron correlation corrections to the energies and radiative transition properties of Th 3 + are studied in detail. • The energies of the 9 D 3 / 2 , 5 / 2 and 8 F 5 / 2 , 7 / 2 levels, a few g factors, and many transition properties of Th 3 + are reported for the first time. Energies, Landé g factors, line strengths, transition probabilities, and oscillator strengths for electric dipole (E1), electric quadrupole (E2), and magnetic dipole (M1) transitions arising from the n S 1 / 2 (n =7-10), n P 1 / 2 , 3 / 2 (n =7-9), n D 3 / 2 , 5 / 2 (n =6-9), n F 5 / 2 , 7 / 2 (n =5-8), and n G 7 / 2 , 9 / 2 (n =5,6) energy levels in Th 3 + , are calculated using the singles and doubles approximation of the relativistic coupled-cluster (CCSD) method. The data are compared with available experimental and theoretical results, showing a good agreement. To the best of our knowledge, many results are reported for the first time. This work reports a high-precision atomic property calculation of Th 3 + and is of great significance for future spectral analysis and precision experiments targeting various applications. [ABSTRACT FROM AUTHOR]

We have performed calculations for Cu-like to Br-like neodymium (Nd) ions using the multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction (RCI) approaches. An extensive set of fine structure energy levels, lifetimes, wavelengths, and radiative transitions for electric and magnetic multipole transitions is provided. We systematically include the electronic correlation effects between valence electrons and two subshells of core electrons. In the RCI procedure, both the Breit interaction and the leading quantum electrodynamic effects are taken into account. The reliability and accuracy are confirmed by comparing our results to accessible experimental and theoretical data. [ABSTRACT FROM AUTHOR]

We report two new ternary metal halide scintillators, KBa 2 I 5 and K 2 BaI 4 , activated with divalent europium. Single crystal X-ray diffraction measurements confirmed that KBa 2 I 5 has a monoclinic structure (P2 1 /c) and that K 2 BaI 4 has a rhombohedral structure (R3c). Differential scanning calorimetry showed singular melting and crystallization points, making these compounds viable candidates for melt growth. We grew 13 mm diameter single crystals of KBa 2 I 5 :Eu 2+ and K 2 BaI 4 :Eu 2+ in evacuated quartz ampoules via the vertical Bridgman technique. The optimal Eu 2+ concentration was 4% for KBa 2 I 5 and 7% for K 2 BaI 4 . The X-ray excited emissions at 444 nm for KBa 2 I 5 :Eu 4% and 448 nm for K 2 BaI 4 :Eu 7% arise from the 5d–4f radiative transition in Eu 2+ . KBa 2 I 5 :Eu 4% has a light yield of 90,000 photons/MeV, with an energy resolution of 2.4% and K 2 BaI 4 :Eu 7% has a light yield of 63,000 ph/MeV, with an energy resolution of 2.9% at 662 keV. Both crystals have an excellent proportional response to a wide range of gamma-ray energies. [ABSTRACT FROM AUTHOR]

Energy levels and radiative rates are reported for transitions in F-like Ba XLVIII. Configuration interaction has been included among 27 configurations (generating 431 levels) over a wide energy range up to 618 Rydbergs, and the fully relativistic multi-configurational Dirac–Fock method adopted for the calculations. To assess the accuracy, calculations have also been performed with the flexible atomic code, FAC. Radiative rates, oscillator strengths and line strengths are reported for all electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions from the lowest 3 levels, although calculations have been performed for a much larger number of levels. We have made comparisons of our results with existing available results and a good agreement has been achieved. Additionally, lifetimes for all 431 levels are listed. [ABSTRACT FROM AUTHOR]

The probabilities of the electric-dipole transitions 3 d4 p, 3 d4 f-3 d, 3 d4 s, and 3 d4 d in the spectra of nickel-like ions Kr IX, Sr XI, Y XII, Ru XVII, Pd XIX, and Ag XX are calculated semiempirically with the use of published energy levels. [ABSTRACT FROM AUTHOR]

Within the validity of perturbation theory an analytic expression for energy of an electromagnetic pulse with a Gaussian envelope absorbed on an excited inhomogeneously broadened transition is derived and subsequently analyzed. A dependence of the absorbed energy on the pulse duration and relative detuning of its carrier frequency from the central frequency of the transition is analyzed. The range is determined of the problem parameters for which nonlinearity of the considered problem is most pronounced. [ABSTRACT FROM AUTHOR]

Energy levels and radiative rates are reported for transitions in Br-like tungsten, W XL, calculated with the general-purpose relativistic atomic structure package ( grasp ). Configuration interaction (CI) has been included among 46 configurations (generating 4215 levels) over a wide energy range up to 213 Ryd. However, for conciseness results are only listed for the lowest 360 levels (with energies up to ∼43 Ryd), which mainly belong to the 4s 2 4p 5 ,4s 2 4p 4 4d,4s 2 4p 4 4f,4s4p 6 ,4p 6 4d,4s4p 5 4d,4s 2 4p 3 4d 2 , and 4s 2 4p 3 4d4f configurations, and provided for four types of transitions, E1, E2, M1, and M2. Comparisons are made with existing (but limited) results. However, to fully assess the accuracy of our data, analogous calculations have been performed with the flexible atomic code, including an even larger CI than in grasp . Our energy levels are estimated to be accurate to better than 0.02 Ryd, whereas results for radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions. [ABSTRACT FROM AUTHOR]

Energy levels and radiative rates are reported for transitions in Cl-like W LVIII. Configuration interaction (CI) has been included among 44 configurations (generating 4978 levels) over a wide energy range up to 363 Ryd, and the general-purpose relativistic atomic structure package ( grasp ) adopted for the calculations. Since no other results of comparable complexity are available, calculations have also been performed with the flexible atomic code ( fac ), which help in assessing the accuracy of our results. Energies are listed for the lowest 400 levels (with energies up to ∼98 Ryd), which mainly belong to the 3s 2 3p 5 , 3s3p 6 , 3s 2 3p 4 3d, 3s 2 3p 3 3d 2 , 3s3p 4 3d 2 , 3s 2 3p 2 3d 3 , and 3p 6 3d configurations, and radiative rates are provided for four types of transitions, i.e. E1, E2, M1, and M2. Our energy levels are assessed to be accurate to better than 0.5%, whereas radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions. [ABSTRACT FROM AUTHOR]

We report calculations of energy levels, radiative decay rates, and lifetimes for transitions among the 3s23p5, 3s3p6, and 3s23p43d configurations of Cl-like W LVIII. The general-purpose relativistic atomic structure package (GRASP) has been adopted for our calculations. Comparisons are made with the most recent results of Mohan et al. ( Can. J. Phys. 92, 177 (2014). and discrepancies in lifetimes are noted, up to four orders of magnitude in some instances. Our energy levels are estimated to be accurate to better than 0.5%, whereas results for radiative rates and lifetimes should be accurate to better than 20%. [ABSTRACT FROM AUTHOR]

We study the renormalization group effects on neutrino masses and mixing in Minimal Supersymmetric Standard Model (MSSM) by considering a μ-τ symmetric mass matrix at high energy scale giving rise to Tri-Bi-Maximal (TBM) type mixing. We outline a flavor symmetry model based on A4 symmetry giving rise to the desired neutrino mass matrix at high energy scale. We take the three neutrino mass eigenvalues at high energy scale as input parameters and compute the neutrino parameters at low energy by taking into account of renormalization group effects. We observe that the correct output values of neutrino parameters at low energy are obtained only when the input mass eigenvalues are large |m1,2,3|=0.08-0.12 eV with a very mild hierarchy of either inverted or normal type. A large inverted or normal hierarchical pattern of neutrino masses is disfavored within our framework. We also find a preference towards higher values of tan β, the ratio of vacuum expectation values (vev) of two Higgs doublets in MSSM in order to arrive at the correct low energy output. Such a model predicting large neutrino mass eigenvalues with very mild hierarchy and large tan β could have tantalizing signatures at oscillation, neutrino-less double beta decay as well as collider experiments. [ABSTRACT FROM AUTHOR]

The energy levels of the 3 d4 l ( l = 1-3) and 3 p3 d4 l ( l = 0, 1) configurations in the Kr IX ion and the probabilities of radiative transitions to the ground state from these excited states have been calculated within the relativistic perturbation theory using a zero-approximation model potential. The results are shown to be stable within this approximation. The well-known problem of anomalously low accuracy of the calculations of some higher lying singlet levels is considered. [ABSTRACT FROM AUTHOR]

The photoluminescence and scintillation properties of Sn2+-doped gadolinium aluminum-silicate Gd 2 O 3 –Al 2 O 3 –SiO 2 (GAS) glasses with Si 3 N 4 as reducing agent were investigated. The glasses showed a wide emission band in the range of 360–730 nm due to the relaxation of S 1 –S 0 and T 1 -S 0 of Sn2+ luminescent centers. The luminescent intensity of Sn2+-doped GAS glasses reaches maximum at 0.3 mol% Sn2+. The lifetimes of the glasses vary between 6 and 12 μs, which related to the full width at half maximum (FWHM) of the emission spectra. Different oxides were added to explore the relationship between optical basicity and the luminescent properties of glasses. The addition of B 2 O 3 increases the photoluminescence quantum yield (PL QY) of the glasses, which is due to reduction of the Stokes shift and increment of radiative transition probability in energy level transition. The X-ray induced scintillation luminescence of the glasses were observed and studied. • The relationship between Stokes shift and optical basicity of the aluminum-silicate glasses. • High photoluminescence quantum yield (PL QY) in the Sn-doped glasses. • Quantitative analysis of the effect of phonon-electron interaction during Sn2+ luminescence. • The luminescence of Sn2+ centers excited by X-ray was observed for the first time in aluminum-silicate glasses. [ABSTRACT FROM AUTHOR]

Abstract: The Judd–Ofelt parameters of Er3+ in the partially disordered calcium lithium niobium gallium garnet are calculated using absorption spectra. The results ( ; ; ) are used to calculate the radiative lifetimes of the Er3+ energy levels up to 4G11/2 and the branching ratios of the radiative transitions originating on them. The luminescence lifetimes of Er3+ excited levels 4I13/2, 4I11/2, 4F9/2, (4S3/2, 2H211/2) and 2H29/2 are also presented. [Copyright &y& Elsevier]

By applying AUTOSTRUCTURE code, the energies and transitions for allowed (E1) and forbidden (E2, M1, and M2) lines for low-lying configurations in magnesium-like tungsten (W62+) are studied. The electron correlation and relativistic effects are included in computations. Good agreement between our results and available other results are found. The data for E2, M1 and M2 besides some E1 transitions for low-lying levels are presented for the first time. [ABSTRACT FROM AUTHOR]

Extensive and systematic calculations for energy levels and lifetimes are carried out for the lowest 145 levels arising from the 3s23p4, 3s3p5, 3s23p33d, 3p6, 3s3p43d and 3s23p23 d2 configurations in S-like Kr XXI ion using the multiconfiguration Dirac-Fock (MCDF) method. Additionally, radiative data such as transition wavelengths, absorption oscillator strengths, line strengths and radiative decay rates have also been computed for electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1) and magnetic quadrupole (M2) transitions from the ground state. The importance of Breit interaction (BI) and quantum electrodynamics (QED) corrections on the energy levels has also been estimated. To assess the credibility and integrity of our MCDF energies, independent calculations using the relativistic configuration interaction (RCI) approach have also been performed. Detailed comparisons are made between our two sets of results, as well as with other existing experimental and theoretical values, and a good agreement is achieved. The present results will be helpful for the modeling and diagnostics of fusion plasmas. 1. Excitation energies, lifetimes and radiative data of S-like Kr XXI are reported. 2. Breit interaction and quantum electrodynamics effects are analyzed. 3. Two kinds of methods, MCDF and RCI, are employed. 4. The present results are beneficial for fusion research. [ABSTRACT FROM AUTHOR]

• Sensitized Mn2+ luminescence is studied in lithium tetraborate. • Existence of complex luminescence centres is proposed. • Slow or ultrafast Mn2+ luminescence decays occur depending on the excitation energy. • Mechanisms for excitation transfer and luminescence decay acceleration are proposed. Sub-nanosecond luminescence of Mn2+ in Mn-, Sn/Mn-, and Cu/Mn-doped Li 2 B 4 O 7 ceramics is observed under laser excitation. Picosecond pulsed laser radiation (350–370 nm) generates the frequency-doubled radiation directly in a single microcrystal selected in a ceramic sample, with this secondary radiation falling within the impurity-induced VUV excitation bands of doped Li 2 B 4 O 7. These excitation bands are attributed to the creation of an impurity-bound intra-anionic exciton in Me i O 4 –BO 3 –Mn Li complex centres (Me i = Mn, Sn, or Cu). The exciton, in turn, interacts with a nearby Mn2+ ion due to mixing of the Mn2+ excited states with the excitonic states. Exciton annihilation involves Mn2+ energy levels as transient states and causes a sub-nanosecond radiative transition which is accelerated, being accompanied by rearrangement of the surrounding atoms. Excitation within the lower-energy bands is related to the other part of the complex luminescence centre, this is metal-to-ligand intra-anionic charge transfer, which makes an electron accessible to Mn Li , while the hole is transferred only during relaxation of the excited structure. Mn2+ radiative transitions are not forced in the latter case, and slow Mn2+ luminescence decay is observed. [ABSTRACT FROM AUTHOR]

Er3+-doped fluoroaluminate glasses with different concentrations were prepared by using melt-quenching method. Under a 638 nm laser diode pumping, efficient 3.5 μm emission was observed in the 18 mol% Er3+ doped sample, which was ascribed to the Er3+: 4F 9/2 → 4I 9/2 transition. The fluorescence properties such as radiative transition probability, energy level lifetime and branch ratio were predicted by the well-known Judd-Ofelt theory, while the emission and absorption cross-sections were calculated using the Füchtbauer-Ladenburg and McCumber theories, respectively. Both simulated and experimental results show that Er3+-doped fluoroaluminate material is a promising gain medium for 3.5 μm laser applications. • Wide transmission window and high transmittance of fluoroaluminate glass samples. • Double MIR emissions at 3.5 and 2.7 μm were observed, indicating more laser applications could be used. • A complete energy level diagram and details of the energy transition in Er3+ doped fluoroaluminate glass were obtained. • Long lifetimes were measured, especially lifetime at 2.7 μm exhibits advantage than other materials. • Emission and absorption cross-sections and gain spectra at 3.5 μm in 1 mol% Er3+ doped fluoroaluminate glass were calculated. [ABSTRACT FROM AUTHOR]

Abstract: The general solution of the problem of two two-level atoms with degenerate two-photon transitions interacting with a cavity single-mode radiation field in the presence of the Stark shift terms is obtained. The temporal evolution of the atomic inversion for the single-atom case, the entropy squeezing and the atomic variances squeezing are studied. We use the linear entropy and von Neumann entropy to measure the degree of entanglement between the atoms and the field. It has shown that an increase in the value of the Stark shift parameter leads to an increase in the degree of entanglement. These aspects are sensitive to changes in the Stark shift parameter. [Copyright &y& Elsevier]

The high spin level structure of As nucleus is studied by populating the nucleus in Ni(C,p2n)As reaction. Level scheme is revised significantly. Positive parity sequence is extended up to 33/2 and a negative parity side band is identified and extended up to high spins 37/2. In addition about 15 new energy levels and a total of about 25 new gamma transitions were placed in the level scheme. [ABSTRACT FROM AUTHOR]

Abstract: The optical absorption spectra of yttrium aluminum garnet (YAG) crystals doped with Nd3+ ions with different concentrations (0.6at%, 1.0at%, 1.2at%) at the temperature range from 300K to 500K have been measured. The calculated Judd–Ofelt (JO) parameters Ω t (t=2, 4, 6) based on the spectra have been used to predict the radiative transition probabilities, branching ratios and radiative lifetimes of the transitions from 4F3/2 level to the lower levels (4I13/2, 4I11/2, 4I9/2) at each concentration and temperature. The three JO parameters Ω t (t=2, 4, 6), according to the calculation, decrease with the increasing doped concentration at each temperature. The JO parameters Ω 2 and Ω 4 increase, while the parameter Ω 6 decreases with the increasing temperature at each concentration. The branching ratios and radiative transition probabilities of the transitions from the 4F3/2 level to 4I13/2 and 4I11/2 levels decrease, while the transition from the 4F3/2 level to 4I9/2 level increases with the increasing temperature. The obtained results at each concentration and temperature are discussed. [Copyright &y& Elsevier]

Low-lying collective states of 154Sm are studied via the 12C(154Sm,154Sm*) Coulomb excitation reaction at 85% of the Coulomb barrier (570 MeV) using the Gammasphere Ge-detector array. Absolute transition strengths are obtained from the Coulomb excitation cross sections deduced from the relative y-ray yields. The results include transition strengths for E2 decays of energy levels in the low-spin part of the first excited K= 0+ rotational band of 154Sm. The agreement of these results with the confined β-soft rotor model predictions establishes the assignment of this band as a β band. [ABSTRACT FROM AUTHOR]

We investigate the existence of weakly coupled gaslike states comprised of three a particles around an 160 core in 28Si. We calculate the excited states in 28Si using the multiconfiguration mixing method based on the 160 + ³ɑ cluster model. We also include the 160+ 12C and 24Mg + ɑ basis wave functions prepared by the generator coordinate method. To identify the gaslike states, we calculate the isoscalar monopole transition strengths and the overlap of the obtained states with the geometrical cluster wave function and the Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function. The results show that the obtained fourth and twelfth states significantly overlap with the THSR wave function. These two states clearly coexist with the 160 + 12C cluster states, emerging at similar energies. The calculated isoscalar monopole strengths between those two states are significantly large, indicating that the states are members of the excitation mode. Furthermore, the calculated root-mean-square radii for these states also suggest that a layer of gaslike three α particles could exist around the surface of the 160 core, which can be described as a "two-dimensional gas" in the intermediate state before the Hoyle-like three-α states emerge. [ABSTRACT FROM AUTHOR]

The O+2 state in 34Si has been populated at the GANIL-LISE3 facility through the &bgr; decay of a newly discovered 1+ isomer in 34Al of 26(1) ms half-life. The simultaneous detection of e+ e- pairs allowed the determination of the excitation energy E(0+2) = 2719(3) keV and the half-life T1/2 = 19.4(7) ns, from which an electric monopole strength of &rgr;2(E0) = 13.0(0.9) X 10-3 was deduced. The 2+1 state is observed to decay both to the 0+1 ground state and to the newly observed 0+2 state [via a 607(2) keV transition] with a ratio R(2+1 → 0+1"/2+1 → 0+2) = 1380(717). Gathering all information, a weak mixing with the 0+1 and a large deformation parameter of &bgr; = 0.29(4) are found for the 0+2 state, in good agreement with shell model calculations using a new SDPF-U-MIX interaction allowing np-nh excitations across the N = 20 shell gap. [ABSTRACT FROM AUTHOR]