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Energy levels, hyperfine structure and 2s-2p radiative transition processes of C-like Fe, Co and Ni are studied by performing multiconfiguration Dirac–Hartree–Fock method using the fully relativistic codes GRASP2K. Electron correlation effect on the energies, hyperfine structure constants and radiative transition rates are investigated in detail. Influences of Breit and quantum electrodynamics (QED) effect on energies are studied. Good agreements are found between the results in this work and experimental data. The radiative spectra of the excited states 1s22s2p3 and 1s22p4 of C-like Fe, Co and Ni may provide theoretical support for further experimental study. Since Fe, Co and Ni are important constituent part of experimental apparatus (such as EBIT), the data in this work have important application value for experimental application.

The Li (i = 1–3) subshell integral X-ray fluorescence (XRF) cross sections have been measured for 17 elements with 33 ≤ Z ≤ 51 following photoionization by the Mn K X-rays (EKαβ = 5.96 keV). The Li (i = 1–3) subshell X-rays were measured using a low-energy Ge (LEGe) detector at an emission angle, ψ = 125°, where angle-dependent emission effects, if any, are nullified as P2(cos ψ) ∼ 0. The XRF cross sections were interpreted in terms of available sets of theoretical Li (i = 1–3) subshell photoionization cross sections, radiative transition probabilities, and the atomic vacancy decay parameters, namely, fluorescence (ωi) and Coster-Kronig (fij) yields. A set of L1 subshell fluorescence (ω1) yields was deduced for the elements with 37 ≤ Z ≤ 51 from the present measured Lγ2,3,(4) [L1-N2,3(O2,3)] XRF cross sections. The ω1 values exhibit jumps at Z = 40 and 49, which are identified to be due to cut-off of the L1L2M4,5 and L1L3M4,5 Coster-Kronig (CK) transitions predicted by calculations based on relativistic Dirac-Hartree-Slater (RDHS) model. However, the measured ω1 values are found to differ considerably from those based on the RDHS model calculations for the elements below Z = 50. The pronounced discrepancies between measured and theoretical ω1 values are likely to be due to overestimation of the L1-L2,3M4,5 CK transition rates by a factor of ∼2–3. Our experiential results demand consideration of extra-atomic relaxation from the solid-state effects and exchange splitting in many-body theoretical calculations of the low-energy CK transitions.

A manifold of electronic states of ScS was investigated with special emphasis on the low-lying states X 2Σ+, A´ 2Δ, A 2Π, and B 2Σ+. For all states, potential energy curves were constructed covering internuclear distances from the equilibrium region through the dissociation limit. For the above states, besides providing the most accurate set of theoretical spectroscopic parameters to date, we have also computed dipole moment functions, transitions dipole moment functions, the associated radiative transition probabilities, and radiative lifetimes. For the states known experimentally, X 2Σ+, A 2Π, and B 2Σ+, our results significantly expand our present knowledge of the energetic profile of these states thus providing a new perspective for understanding the limited spectral data for this species known so far. For the new state, A´ 2Δ, yet unobserved experimentally, our results are sufficiently reliable and accurate to guide spectroscopists on further studies of this species.

Dielectronic recombination (DR) rate coefficients for the ground levels of low ionization state W q + ( q = 5 − 10 ) ions have been obtained by an ab-inito level-by-level calculation using the flexible atomic code (FAC) based on relativistic jj coupling scheme and independent process, isolated resonance, distorted wave approximation. The radiative transition calculation in the original FAC has been adapted into parallel programming for time effective dealing with so many resonance levels of the complex open 4f, 5p, or 5d-shell structure ion. Core excitations Δ n c = 0 , 1 of 4f, 5p, and 5d (W 5 + ), Δ n c = 2 of 4f, and Δ n c = 0 of 4d (W 7 + ), and 5s (W 8 + ) are included to the total DR rate coefficient. The core excitations Δ n c = 0 , 5p → 5l and Δ n c = 1 , 4f → 5l mainly contribute to the total DR rate coefficients. The strong resonances involved in the DR are analyzed and the total DR rate coefficients are compared with available previous ab-initio predictions and with ADAS data by a simple semiempirical formula.

Temperature and radical concentration are the two most important factors affecting NOx emissions in the methane combustion, while chemiluminescence is from the radiative transition of excited radicals, related to the heat release closely. Accordingly, there must be an implicit link between NOx formation and chemiluminescence. Chemiluminescence and NOx emission characteristics under various equivalent ratios ( φ ) and swirl numbers (S) have been investigated in a lean premixed dual-swirl flame. The results show that φ and S have different effects on chemiluminescence intensities and flame structures, and the change trend of NOx emissions is the same as chemiluminescence intensities. More importantly, a linear relationship between chemiluminescence intensities and NOx emissions was proposed and tested, making it possible to monitor NOx emissions in combustion by the non-intrusive and cost-effective chemiluminescence technique.

In this paper, we calculate the energy and radiative transition properties of singly charged Ra using the singles and doubles approximated relativistic coupled-cluster method. The excitation energies of the (7 - 12) S 1 / 2 , (7 - 12) P 1 / 2 , 3 / 2 , (6 - 10) D 3 / 2 , 5 / 2 states in Ra + are reported. The results are compared with available experimental results, showing a good agreement. Accurate values along with their uncertainties of the electric-dipole (E1), electric-quadrupole (E2), and several important magnetic-dipole (M1) matrix elements for transitions in singly charged Ra are determined by the relativistic coupled-cluster method at different approximations. Using these computed E1, E2, and M1 matrix elements, we also provide the related radiative transition properties of Ra + , including line strengths, oscillator strengths, and transition rates. Furthermore, we also investigate the role of electron correlation in these properties. To the best of our knowledge, many results are reported for the first time. Present work reports a high-precision atomic property calculation of Ra + and is beneficial for present and future experiments using Ra + targeting various applications such as atomic clocks and studies of parity non-conservation.

Using the multiconfiguration Dirac–Hartree–Fock and the relativistic configuration interaction methods, a consistent set of transition energies and radiative transition data for the main states of the 2 s 2 2 p 4 , 2 s 2 p 5 , 2 p 6 , 2 s 2 2 p 3 3 s , 2 s 2 2 p 3 3 p , 2 s 2 2 p 3 3 d , 2 s 2 p 4 3 s , 2 s 2 p 4 3 p , and 2 s 2 p 4 3 d configurations in O-like Ions between Ar XI ( Z = 18 ) and Cr XVII ( Z = 24 ) is provided. Our data set is compared with the NIST compiled values and previous calculations. The data are accurate enough for identification and deblending of new emission lines from hot astrophysical and laboratory plasmas. The amount of data of high accuracy is significantly increased for the n = 3 states of several O-like ions, where experimental data are very scarce.

Using the multiconfiguration Dirac-Hartree-Fock (MCDHF) and the relativistic configuration interaction (RCI) methods, a consistent set of transition energies and radiative transition data for the lowest 150 states of the 3 s 2 3 p 3 , 3 s 3 p 4 , 3 s 2 3 p 2 3 d , 3 s 3 p 3 3 d , 3 p 5 , and 3 s 2 3 p 3 d 2 configurations in P-like Ge XVIII is provided. To assess the accuracy of the MCDHF transition energies, we have also performed calculations using the many-body perturbation theory (MBPT). Comparisons are made between the present MCDHF and MBPT data sets, as well as with other available experimental and theoretical values. The resulting accurate and consistent MCDHF data set will be useful for line identification and modeling purposes. These data can be considered as a benchmark for other calculations.

The double electron E1 transition energies, probabilities, and oscillator strengths between the 2 s 2 p n and 1 s 2 2 p n − 1 ( 1 ≤ n ≤ 6 ) configurations of Xe q + ( 47 ≤ q ≤ 52 ) ions with different spectator electrons have been calculated based on the multi-configuration Dirac-Hartree-Fock method. A reasonable electron correlation model is constructed with the aid of the active space method. The finite mass of nuclear, Breit interaction and QED effects have also been included. The calculated results are in good agreement with the available data. The theoretical spectra of different spectator electrons of the double K hole state have been predicted. The spectator electron effects on the transition spectra have been analyzed in detail. The present results will be helpful for analyzing the high energy X-ray spectrum observed from the interaction between high energy highly charged ions and the surface.

On the basis of a fully relativistic multiconfiguration Dirac–Fock method, a systematic study has been carried out for the energies, radiative and non-radiative (Auger) decay processes of the core-excited states 1s2p 3 for Be-like ions with Z =8–54. The energies and radiative transition rates are smoothly varying functions of Z . Auger rates do not change significantly with Z as the radiative rates do. Electron correlation effects on the energies and the radiative transition rates are investigated. Good agreement is found between our results and other theoretical data.

Energy levels and the radiative decay processes of the core-excited configurations 1s2s 2 2p and 1s2p 3 of Be-like ions with Z = 8–54 are studied. Electron correlation effect on the energy levels and the radiative transition rates are studied in detail. Except for E1 radiative transition rates, the E2, M1 and M2 forbidden transitions are also explored. Further relativistic corrections from the Breit interaction, quantum electrodynamics and the finite nuclear size are included in the calculations to make the results more precise. Good agreement is found between our results and other theoretical data.

Luminescence generated by a plate-impact-induced shock wave has been detected from a Ce-doped phosphor powder, Ce3+:Y3Al5O12. The observed luminescence spectrum shows two strong bands in the visible region: one at ∼410 nm and the other at ∼530 nm. The second band is very similar to the well-known luminescence band of Ce:YAG corresponding to the T2g → 2F transition, but the first band is hardly observed in the photoluminescence spectrum. One possible mechanism for the first band is the radiative transition from the higher energy excited level of Ce3+ to the ground level, namely Eg → 2F.

Energy and radiative transition rates of the 1s2s ( 1 , 3 S ) 3p levels of Li-like ions with 5 ⩽ Z ⩽ 10 are calculated using a multiconfiguration Dirac-Fock approach including quantum-electrodynamic and electronic correlation corrections. The importance of the electronic correlation on the radiative transition probabilities is assessed in detail.

The natural widths, lifetimes, and fluorescence yields for the double K -shell hole states have been calculated for atoms with 10 ≤ Z ≤ 30. The Grasp 2018 package was adopted to carry out a systematic computation of the K h α 1 , 2 and K h β 1 , 3 radiative transition rates and Fac was used to calculate the K K − K L L , K K − K L M , and K K − K M M non-radiative Auger transition rates. The dependence of the radiative and non-radiative rates on the existence of 3 s , 3 p , 3 d , or 4 s spectator holes is studied.

The radiative transition properties of Eu3+ doped materials can hardly be quantitatively evaluated via traditional Judd-Ofelt (J–O) calculation procedure owing to the lack of available transitions in the absorption spectra. In this work, a new J–O calculation route was proposed and employed to Eu3+ doped alkali borate glasses. Three sets of J–O parameters were obtained by using, respectively, the absorption, emission and excitation spectra, and the average J–O parameters involving more electric dipole transitions than in any individual spectrum were suggested to be used for quantificationally presenting radiative transition properties of Eu3+ in the studied glasses. The radiative transition lifetime of 5D0 level derived by using the J–O parameters was compared with the measured one, and good agreement was achieved. This fact indicated that the proposed J–O calculation route is practicable. Furthermore, the radiative transition rates and fluorescence branching ratios for Eu3+ in the studied borate glasses were calculated.

For understanding silicon chemistry in the interstellar medium, identification of large number of Si-bear- ing molecules in the medium is required. Ten Si-bearing molecules (SiO, SiS, SiC, SiN, c-SiC2, SiCN, SiNC, c- SiC3, SiC4 and SiH4) have been identified in the interstellar medium. Izuha et al. (1996) recorded micro- wave spectrum of H2CSi and made an unsuccessful attempt for its identification in IRC + 10216, Ori KL, Sgr B2 through its 717 � 616 transition at 222.055 GHz. Using rotational and distortional constants for H2CSi (Izuha et al., 1996), we have calculated radiative transition probabilities and line strengths for tran- sitions between rotational levels lying below 100 cm � 1 . We have found that 7 lines of ortho-H2CSi and 3

The fluorescence properties of 2.7 μm emission and energy transfer mechanism of Ho 3+ /Er 3+ co-doped fluoride glass (ZBYA) have been investigated in the present paper. Ho 3+ strengthens the Er 3+ : 2.7 μm emission in the ZBYA glasses due to the energy transfer from Er 3+ to Ho 3+ , while the 1.5 μm emission decreases dramatically. The optimized concentration ratio of Er 3+ to Ho 3+ is found to be 1:1 in our glass system. The absorption and emission spectra are tested and the sample possesses large emission cross section (16.5 × 10 −21 cm 2 ) around 2.7 μm along with larger radiative transition probability (25.11 S −1 ) on the basis of Judd–Ofelt and Fuchtbauer–Ladenburg theories. Additionally, the energy transfer microparameters are calculated using Forster–Dexter theory and the result shows the energy transfer coefficient of Er 3+ : 4 I 13/2 → Ho 3+ : 5 I 7 is 24 times larger than that of Er 3+ : 4 I 11/2 → Ho 3+ : 5 I 6 . Our results show that Er 3+ : 2.7 μm emission can be sensitized by Ho 3+ efficiently, and this Er 3+ /Ho 3+ -codoped fluoride glasses might have potential application in mid-infrared lasers.

This paper focuses on the calculation of the radiative transition probabilities for the main diatomic molecules contributing to the discrete radiation of CO–H2 syngas plasma. We propose extensive tables of rovibrational transition probabilities for the main electronic systems of OH, CH, CH+, CO and CO+. The rotational dependence of the nuclear wave-functions was included in our calculations to take into account the coupling between the rotational and vibrational motions. References are also given to data for O2, C2 and H2 molecules already published in the literature. The calculations were performed using the Rydberg–Klein–Rees (RKR) inversion procedure for the reconstruction of the potential-energy curves and an improved Numerov-type method was used to obtain the rovibrational wave-functions by solving the radial Schrodinger equation. We rigorously selected the most up-to-date equilibrium spectroscopic constants for the RKR procedure and the most accurate electronic transition moment functions (ETMF) available in the literature. The results obtained with this procedure were systematically validated by comparison with available experimental observations.

Series of 76GeS2·19Ga2S3·5AgCl (GGA) chalcohalide glasses doped with or codoped with Dy3 +, Tm3 + were prepared in this work. Systematical detection of absorption and emission spectra in the near-infrared and mid-infrared region was conducted. For the Dy3 + sole-doped GGA chalcohalide glasses, mainly due to the relatively low efficiency of pumping absorption and poor radiative transition probabilities of mid-infrared emissions, the mid-infrared emissions were hardly to be detected. Through the codoping of Tm3 + with high concentration, several intrinsical processes including the enhancement of pumping absorptive efficiency at 808 nm, cross relaxation process of Tm3 +: 3H4 + 3H6 → 3F4 + 3F4 and energy transfer process of Tm3 +: 3F4 → Dy3 +: 6H11/2 are carried out, therefore relatively strong mid-infrared emissions at about 2900 and 4300 nm have been clearly observed.

The low-lying electronic states ( X 2 Π, a 4 Π, b 4 Σ − , B 2 Π, 1 2 Φ, A 2 Δ and B ′ 2 Σ + ) of the NS molecule are computed at the AV5Z/CASSCF/MRCI+Q+DK level of theory. The potential energy curves are presented for these states; the corresponding spectroscopic constants are reported. Electronic transition moment functions, Einstein coefficients, Franck–Condon factors and radiative lifetimes for the B 2 Π –X 2 Π, B ′ 2 Σ + – X 2 Π and A 2 Δ– X 2 Π system have been calculated. The F–C factors of the B 2 Π are in good agreement with the corresponding RKR data. The B ′ 2 Σ + state possesses a barrier in the potential energy curve, located at about 2.16 A. The height of the barrier is predicted to be 7890 cm −1 .

Spectroscopic properties of Sm3 +-doped phosphate and fluorophosphate glasses of the composition (60 − x / 2) P2O5 + 15 K2O + (15 − x / 2) SrO + 10 Al2O3 + x Sm2O3 (PKSASm) and (54 − x / 2) P2O5 + 14 K2O + 10 KF + (13 − x / 2) SrO + 9 Al2O3 + x Sm2O3 (PKFSASm), where x = 0.1, 0.5, 1.0, 2.0, 4.0 and 6.0 mol%, have been investigated. The oscillator strengths and the intensity parameters (Ω2, Ω4 and Ω6) have been determined using the Judd–Oflet theory, which in turn is used to predict the radiative transition probability (AR), radiative lifetime (τR) and branching ratios for the fluorescent 4G5/2 level. The higher stimulated emission cross-sections, 12.27 × 10− 22 and 14.12 × 10− 22 cm2 have been observed for the 4G5/2 → 6H9/2 transition of PKSASm10 and PKFSASm10, respectively. The non-exponential nature of the decay curves of the 4G5/2 level increases with increase in Sm3 + ion concentration accompanied by decrease in lifetime. The non-exponential decay curves have been best fitted to the generalized Yokota–Tanimoto model indicating that the energy transfer among optically active ions is through dipole–dipole interaction.

It is reported that Auger-free (AF) luminescence appears with two bands at 4.5 and 6.3 eV in Rb 2 ZnCl 4 . This luminescence originates from a radiative transition of the Cl 3p valence electrons into the Zn 3d outermost-core holes. The present work is the first observation of AF luminescence due to interatomic p–d transitions in halide crystals. The appearance of two AF luminescence bands suggests the existence of two types of AF transitions following core hole creation. A largely Stokes-shifted luminescence band is also found to appear at 1.9 eV. This band has an excitation threshold at the fundamental absorption edge, and is ascribed to the radiative decay of a self-trapped exciton.

This article presents the optical properties of Tb3+ in lead fluoroborate glasses of the type X PbF2·(89–X)B2O3·10 Al2O3·1Tb2O3 (where X=8, 12, 16, 20, 24, 28, 34 and 36). The standard Judd–Ofelt model was applied to the room temperature absorption intensities of Tb3+ (4 f8) to determine the phenomenological intensity parameters Ω2, Ω4 and Ω6. These parameters have been used to calculate radiative transition probabilities (Arad), lifetimes (τR) and branching ratios (βR) for the excited level 5D4. The predicted values of τR are compared with the measured values for 5D4 level for eight glass compositions (Glass (A–H)). Among the eight-terbium glasses Glass A with 8 mol% of PbF2 (as the optimum content) has revealed an intense green emission with maximum life time and higher quantum efficiency. The stimulated emission cross section σ(λP) is also evaluated for the 5D4→7FJ (J=6, 5, 4 and 3) transitions.

Electroluminescence imaging under forward (EL) and reverse bias (ReBEL) has been applied to correlate defect distribution and breakdown sites in solar cells made of UMG-Si. An InGaAs camera system is used for luminescence detection, providing access to band-to-band and to the sub-band gap radiative transition in silicon. In contrast to previous papers the ReBEL reported here is observed only in the near-infrared (1.25 eV - 0.6 eV) spectral range and no visible luminescence has been detected. It is found that ReBEL intensity correlates with dark I-V characteristics. The overall distribution of breakdown sites in cells is different from the distribution of dislocations exhibiting luminescence at 0.8 eV (grain boundaries, defects). For the first time, a spatial separation between such defects and breakdown sites is clearly established by high resolution images, giving evidence that the defects showing sub-band gap luminescence do not take part in breakdown. It is further concluded that such radiative defects reduce the affinity for breakdown in their vicinity.

Here we present the results of our theoretical study of the optical characteristics (lifetimes, IR absorption coefficient, Raman gain coefficient) for small-radius optical centers in subwavelength spherical and ellipsoidal nanocrystals embedded in a dielectric medium.

Absorption and emission spectra of Sm 3+ and Eu 3+ co-doped lithium borate glass of the following composition: x Sm 2 O 3 + (100 − x )[0.84H 3 BO 3 + 0.15Li 2 O + 0.01Eu 2 O 3 ], where x = 0.0, 0.1, 0.2, 0.5, 0.6 and 0.7 mol%, have been reported. The concentration of Sm 3+ was varied keeping the Eu 3+ concentration fixed at 0.01 mol%. Optical absorption and emission spectra have been measured in the spectral range from 350 to 2400 nm. The oscillator strength, Judd–Ofelt intensity parameters, branching ratios and radiative transition probabilities were calculated. The obtained results are discussed and compared with other literature data for Eu 3+ in various compounds.

Extensive non-relativistic variational calculations for estimating the energy values of 2 pnd ( D o 1 , 3 ) states [ n = 3 – 6 ] of two electron atoms (He, Li + , Be 2 + ) and 2 pnp ( P e 1 ) [ n = 3 – 8 ] and 2 pnp ( P e 3 ) states [ n = 2 – 7 ] of Be 2 + under weakly coupled plasma screening have been performed using explicitly correlated Hylleraas type basis. The modified energy eigenvalues of P e 1 , 3 states arising from two p electrons of Be 2 + ion and D o 1 , 3 states due to 2 pnd configuration of Li + and Be 2 + ion in the Debye plasma environment are being reported for the first time. The effect of plasma has been incorporated through the Debye screening model. The system tends towards gradual instability and the number of bound states reduces with increasing plasma coupling strength. The wavelengths for 2 pn ′ p ( P e 1 ) [ n ′ = 3 – 8 ] → 2 pnd ( D o 1 ) [ n = 3 – 6 ] and 2 pn ′ p ( P e 3 ) [ n ′ = 2 – 8 ] → 2 pnd ( D o 3 ) [ n = 3 – 6 ] transitions in plasma embedded two electron atoms have also been reported.

Praseodymium-doped borovanadate glasses were prepared by conventional quenching melt technique. The prepared composition was [90 Na2B4O7–(10 − x)V2O5–x Pr6O11], x = 0, 0.5, 1, 2, 4, 6, 8 and 10 mol%. Optical absorption spectra have been investigated in the spectral range from 195 to 2500 nm. Experimental oscillator strengths of the observed bands have been estimated and used for calculating the Judd–Ofelt (JO) intensity parameters. Radiative transition probabilities as well as branching ratios were calculated. The radiative lifetime of the 1D2 and 3P0 levels was varied from ca. 344 to 808 μs and ca. 30 to 63 μs respectively. The optimum Pr concentration at which the branching ratios have the maximum values was obtained at 1 mol%.

Tm 3+ and Ho 3+ co-doped TeO 2 –ZnO–Bi 2 O 3 (TZB) glasses were prepared by the conventional melt-quenching method. Two micrometre emission properties of the TZB glasses exited by 808 nm Laser Diode (LD) were analyzed and discussed. The Judd–Ofelt parameters, spontaneous radiative transition probabilities and radiative lifetime of Ho 3+ were calculated based on the absorption spectra by using Judd–Ofelt theory. The absorption spectra and fluorescence spectra were measured. The predicted spontaneous radiative transition rate of 5 I 7 → 5 I 8 of Ho 3+ is as high as 466.8 s −1 . The result of fluorescence spectra indicates that the maximum emission intensity of Ho 3+ 2.0 μm and of Tm 3+ 1.47 μm emission can be achieved at the concentration of 1 mol% Tm 2 O 3 and 1 mol% Ho 2 O 3 in TZB glasses. The maximum absorption and emission cross-section of Ho 3+ near 2.0 μm are 0.87 × 10 −20 cm 2 at 1951 nm and 1.07 × 10 −20 cm 2 at 2047 nm, respectively.

This work was partially supported by a Large Interdisciplinary Grant award from the Ohio State University. The computational work was carried out on the Cray X1 and Itanium 4 cluster at the Ohio Supercomputer Center in Columbus Ohio. C. Sur acknowledges Dr. Rajat Chaudhuri for helpful discussions and developing codes for relativistic coupled cluster calculations.

It is shown that quark mass dependence induced by one-loop corrections to the Breit–Fermi spin-dependent one-gluon-exchange potential permits an accurate determination of heavy–light meson masses. Thus the Ds(2317) is a canonical cs¯ meson in this scenario. The multiplet splitting relationship of chiral doublet models, M(1+)−M(1−)=M(0+)−M(0−), holds to good accuracy in the D and Ds systems, but is accidental. Radiative transitions and bottom flavoured meson masses are discussed.

Franck–Condon factors, Einstein coefficients, and band oscillator strengths have been calculated for the most prominent diatomic radiative transitions found in high-temperature CO 2 – N 2 gases and plasmas. A bibliographic review has allowed selecting the most up-to-date spectroscopic constants, which were used for rebuilding the electronic states potential curves through the Rydberg–Klein–Rees method. Vibrational wavefunctions have been determined for such potential curves and combined with the most up-to-date electronic transition moments found in the literature, in order to determine the transition radiative properties. The proposed set should provide an useful and accurate spectroscopic database for the determination of the radiative properties of CO 2 – N 2 gases and plasmas.

The present work aims to study the variation of Judd–Ofelt intensity parameters, radiative transition probabilities, absorption and emission cross sections with alkali content in three different Sm3+-doped mixed alkali borate glasses. Mixed alkali borate glasses in the composition 67H3BO3·xLi2CO3(32-x)Na2CO3·1Sm2O3, 67H3BO3·xLi2CO3(32-x)K2CO3·1Sm2O3 and 67H3BO3·xNa2CO3(32-x)K2CO3·1Sm2O3 with x = 8 , 12, 16, 20 and 24 mol% were prepared by quenching melts consisting of the above chemicals (850–950 °C, 1–2 h) between two brass plates. Judd–Ofelt theory is used to study the spectral properties and to calculate the radiative transition probabilities and branching ratios. The predicted radiative transition probabilities (Aed), branching ratios ( β ) and integrated absorption cross-sections ( Σ ) for certain transitions are reported. From the emission spectra, emission cross-sections ( σ P ) are obtained for the four transitions, 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 and 4G5/2→6H11/2 of Sm3+ ion in these mixed alkali borate glasses. Optical band gaps (Eopt) and absorption edges are reported for the three Sm3+-doped mixed alkali borate glasses.

Optical spectra of Dy3+:LiYF4 (Dy3+:YLF) single crystal were analyzed using Judd–Ofelt theory and discrete variational multielectron method (DVME). Oscillator strengths (OS) of transitions up to 39 000 cm−1 in the absorption spectrum, branching ratios and nonradiative transition rates were calculated; assignment of the absorption transitions was given. A good agreement between calculated and experimental values of branching ratios for transitions from quartet 4 F (3) 9/2 to the low-lying sextet levels is demonstrated. Ab initio calculations of OS were performed.

The collision broadenings of the Na D lines were calculated from the transmission measurements of the vapor in sub-μTorr and μTorr regions by modeling the line shape with the Voigt profile. From the line shift, the average time between collisions is calculated. The ratio of the width to the shift is of the order of 10 −4 implying that the impact approximation is valid. Expanding the line widths and shifts in powers of the product of number density and mean velocity of the atoms, the radiative transition probabilities, and the fundamental line shape constants: collision cross-sections and asymmetry of the lines are obtained. Moreover, from the line shifts and using the estimated value of the optical collision diameter obtained from the line widths, the average C 3 value, over the temperature ranges the experiment covers, is calculated.

Accurate potential energy curves, transition moments, spectroscopic constants, radiative transition probabilities, and lifetimes for the states X 3 Σ − , (1) 3 Π , and (2) 3 Σ − of BeC, MgC, and CaC are reported using high level calculations. Diagonal transitions dominate for the (2) 3 Σ − → X 3 Σ − system, with band origins falling at 745, 648, and 770 nm, and an intensity ratio of 6,3,1, respectively for BeC, MgC, and CaC. Radiative lifetimes for v ′ =0 are equal to 0.48, 1.45, and 3.29 μs for the state (2) 3 Σ − , and equal to 13.57, 10.44, and 9.62 μs for the state (1) 3 Π for BeC, MgC, and CaC.

Adopting a 2π geometrical configuration, target criteria for measuring fluorescence X-rays have been established. These criteria satisfy the Bambynek et al. (Rev. Mod. Phys. 44 (4) (1972) 716) suggestion regarding the optimum thickness of the target, balancing the production and attenuation of the fluorescence X-rays. The K-shell fluorescence cross section or K X-ray production cross section, σK, the K-shell fluorescence yield, ωK, and the ratio between the widths of the radiative transition and the Auger transition, ΓRK/ΓAK, have been measured for some high-Z elements (62⩽Z⩽82). The results are compared with theoretical, fitted and experimental values corresponding to several geometries. Good agreement indicates that the present method is a suitable alternative for measuring K-shell fluorescence parameters.

The K-shell fluorescence yield, fluorescence cross-section and ratio between the radiative transition width and the Auger transition width have been measured for medium- Z elements, 30⩽ Z ⩽50, using a 2 π geometrical configuration method. The results are compared with standard theoretical, semi-empirical, and fitted values and also with the other experimental data.

The paper is devoted to the memory of my teacher and friend Christian K. Jorgensen who has written the pioneering works on complexes of Rare Earths (RE).

K shell radiative transition probabilities and K, L 2 and L 3 shell/subshell fluorescence yields were measured using the K β /K α intensity ratio for seven elements in the atomic number range 30≤ Z ≤40 (Zn, As, Se, Rb, Sr, Y and Zr). The targets were irradiated with γ photons of energy 59.5 keV from Am-241. The obtained values were compared with the theoretical values. It was observed that the present values agree with previous theoretical results. The L 2 and L 3 subshell fluorescence yields were the first measured for the present elements.

This paper presents a review of recent investigations on disordered materials such as glasses and disordered crystals doped with chromium. The main goal of the research was the determination of the lattice disorder and the influence of this disorder on the properties of the luminescence centres and the nonradiative processes. The most important and novel are theoretical approaches that allow recovery of the distribution of the lattice disorder and the crystal-field parameters from the spectroscopic data.

The vacancy transfer probabilities of K to L 1 , L 2 and L 3 shells were measured using a new approach. Those measuring L X-ray yields from targets excited by 59.5-keV incident photons above the K edge of elements were detected with a high-resolution Si(Li)-detector. For comparison with experimental results, using available data on radiative and radiationless transitions theoretical calculations were made. The radiative transitions of these elements were observed from the relativistic Hartree–Slater model. The radiationless transitions were observed from the Dirac–Hartree–Slater model. The measured results were found to be in good agreement with theoretical values.

The polarizations of the χ states produced in high energy collisions can be derived from the dilepton decay distributions of the daughter J / ψ or ϒ mesons, with a reduced dependence of the measurement on the details of photon reconstruction and simulation, and eliminating the dependence of the polarization measurement on the actual details of the multipole structure of the radiative transition.

Measurements at high target pressures of the radiative lifetime and the collisional deactivation of the N 2 C state are currently being published. It is shown in the present Comment that such measurements may yield too small deactivation rates in view of reverse transfer effects.

The cross section of the process e + e − → ηγ has been measured in the 600–1380 MeV c.m. energy range with the CMD-2 detector. The following branching ratios have been determined: B ( ρ → ηγ )=(3.28±0.37±0.23)×10 −4 , B ( ω → ηγ )=(5.10±0.72±0.34)×10 −4 , B ( φ → ηγ )=(1.287±0.013±0.063)×10 −2 . Evidence for the ρ (1450)→ ηγ decay has been obtained for the first time.

Factors determining the low temperature fluorescent transition rate of the luminescence of rare earth implanted semiconductors are studied. Photocarrier induced Auger deexcitation has been used to separate the radiative transition rate from the fluorescent one for Er-, Er and Ne-, Er and O-implanted Si and Ho-implanted GaAs.

The photon cascade emission of Gd 3+ ions under 8 S 7/2 → 6 G J excitation is observed in GdBaB 9 O 16 . Under the 202 nm excitation, a red and a near infrared radiative transition from 6 G J states, 6 G J → 6 I J and 6 G J → 6 P J occur followed by an ultraviolet emission of 6 P J → 8 S 7/2 . The absence of emission from 6 D J and 6 I J states is attributed to the effective multiphonon 6 D J → 6 I J and I J → 6 P J relaxation in this lattice.

The intensity and decay profile of the photoluminescence (PL) in glassy GeSe2 are measured as a function of temperature from 2 to 200 K. The intensity decreases exponentially in the temperature region >100 K. The complicated temperature dependence of the decay profile as well as the dependence of the intensity are explained in a unified framework by adopting a model of the luminescent sites whose thermal activation energy for the non-radiative process is distributed. We show that the intensity variation is affected by the non-radiative process while the decay life time depends almost only on the radiative transition rate.

It is known that some radiative transition arrays, between configurations of opposite parities, are forbidden when the configurations are pure, and allowed when they are perturbed by configuration interaction. A method is described for computing the total strengths of such arrays, through the use of compact formulas, when the perturbing and the perturbed configurations lie far apart in energy. Numerical applications to the Mo XVI spectrum are compared with the results of detailed line-by-line calculations.

L-subshell ionisation cross-sections for Ta, W and Pt by proton impact in the energy range of 2‐5.2 MeV have been determined from the experimental data on X-ray production cross-section and the currently available radiative transition probabilities, fluorescence and Coster‐Kronig factors of Krause, Werner and Jitschin and Xu. The measured ionisation cross-sections and their ratios are compared with the results of ECPSSR and RPWBA-BC theoretical calculations and previously reported experimental results. The deviations in the various L subshell ionisation cross-sections with three sets of decay yield parameters are found to be less than 20%. Our results of absolute L-subshell ionisation cross-sections and their ratios are in better agreement with the theoretical calculations as compared to previously reported experimental results. The L-subshell coupling eAects are found to be weak for the elements of Ta, W and Pt in the energy region 2‐5.2 MeV by proton impact. ” 2000 Elsevier Science B.V. All rights reserved.