Photoabsorption resonances of Na20, Na21Cl and Na22Cl2 clusters

Plasma resonance profiles in the visible part of the spectrum were measured by photoabsorption spectroscopy for the clusters Na₂₀, Na₂₁Cl and Na₂₂Cl₂ in a beam. The resonance positions in Na₂₀ and Na₂₁Cl are close, suggesting that the Cl^- ion does not locate at the center of the metallic droplet and does not strongly modify the effective valence electron density. The spectrum of Na₂₂Cl₂ is noticeably dissimilar to the other two, raising the possibility of structural differences and/or incomplete charge transfer.     

Different Eu-centres in CaS:Eu, Cl

The EPR and luminescence properties of CaS:Eu,Cl-luminophors with different Cl and Eu concentrations are studied. The Mössbauer effect on ¹⁵¹Eu is measured. Eu as a dopant is shown to form mainly Eu³⁺-centres rather than Eu²⁺-centres. Eu oxidation to Eu³⁺ is due to the formation of V_CaCl_S-associates in the CaS lattice. Besides the Eu²⁺-centres of high symmetry various Eu²⁺-Eu²⁺ pairs are formed and are responsible for a broad structureless EPR spectrum and for an infrared shift of the Eu²⁺ luminescence band.     

Sensitized luminescence of SrS:Dy,Cu,Cl phosphor

SrS:Dy,Cu,Cl phosphors for a fixed Dy concentration and different Cu concentrations were prepared by solid-state reaction. Studies on the structural and optical properties of the samples were carried out. From analysis of photoluminescence measurements, it was observed that the excitation in the absorption bands of Cu⁺ ion leads to transfer of energy to Dy³⁺ ion, thereby enhancing the intensity of its luminescence.     

Gamma ray energies and 36Cl level scheme from the reaction 35Cl(n, γ)

The γ-ray spectrum emitted after thermal neutron capture in ³⁵Cl has been studied by use of the crystal and pair spectrometers installed at the ILL high flux reactor. We identified about 400 transitions in this reaction 326 of which were placed into the ³⁶C1 level scheme; several new states were found. The level energies up to 3.5 MeV were measured with a precision of 5–20 eV relative to the 412 keV ¹⁹⁸Au standard, those above 3.5 MeV with a precision of ¹⁰ppm. The neutron binding energy was determined to be E_B = 8579.68(9) keV.     

The S34 (p, γ) Cl35 reaction and energy levels of the Cl35 nucleus

A method is presented to eliminate quantitatively the decay time of the radioactive source and all systematic errors caused by the instability of the associated electronics. The essential part of this procedure is a versatile method to measure the random coincidences together with the sum of true and random coincidences under the same experimental conditions for both quantities. The proposed method is applied toγ-γ-directional correlation measurements with a five detector apparatus. The construction and function of the device is illustrated. Test measurements with⁶⁰Co prove the usefulness of the method and the capability of the apparatus. The investigation of twoγ-γ-cascades in the decay of¹²⁴Sb gives the following values for the coefficients of the correlation function 1,69-0,603 MeV-cascade:A ₂=?0,065±0,003A ₄=+0,001±0,005 2,09-0,603 MeV-cascade:A ₂=?0,056±0,008A ₄=+ 0,006±0,008     

The reaction 36S(p, γ)37Cl: (II). Lifetimes,spins and parities of 37Cl levels

Analysis of the γ-ray angular distributions measured at 16 ³⁶S(p, γ)³⁷Cl resonances yields the spins and/or parities of 21 bound states of ³⁷Cl in addition to the resonance spins. Among the latter are four $\text{J =}\text{1}\text{2}$ resonances. For several other bound states the possible spins have been restricted. Multipolarity mixing ratios have been deduced from the same data. Lifetimes (or lifetime limits) of 29 bound states have been deduced from DSA measurements.This extensive experimental information allows a comparison with the results of a shell-model calculation for both the even- and odd-parity states of ³⁷Cl. In this calculation either zero, one or two particles are promoted from the 2s_{$\text{1}\text{2}$} or 1d_{$\text{3}\text{2}$} to the 1f_{$\text{7}\text{2}$} or 2p_{$\text{3}\text{2}$} subshells. Up to an excitation energy of about 5 MeV a one-to-one correspondence is found between experimental and calculated levels.     

Thermoluminescence in Ag(Cl,I) mixed crystals

The distribution of traps in AgCl + 1% mol AgI mixed crystals was obtained by thermoluminescent fractional glow technique. The distribution reveals a prominent maximum at 240 meV. These traps are characteristic of mixed crystals. Shallow traps also exist, but they appear to be connected with host AgCl crystal. The nature of the deep trap in mixed Ag(Cl, I) crystals is discussed on the basis of the fundamental optical properties of pure AgI and AgCl crystals.     

Production of L X rays in energetic Cl → Cl collisions

The L X-ray spectrum from Cl⁷⁺ → Cl₂ collisions at 40 MeV is presented. The large number of lines observed are generally found to be consistent with calculations of X-ray transition energies from the “unit flourescence yield configuration”, 1s²2s²2pⁿ3s¹. The calculations indicate large X-ray energy splittings for transitions from different multiplet states. The assumption of statistical population of the multiplets is found to be consistent with the intensities of the observed lines.     

35Cl quadrupolar constants obtained by solid-state NMR: study of chlorinated Al-O-P clusters,involving OH...Cl hydrogen bonds

Simulation of static and MAS NMR spectra obtained at high field (B(0) = 14.08 T) and high spinning frequency (up to nu(rot) = 22 kHz) allows the determination of 35Cl quadrupolar parameters for various cubane-shaped, cage-like and cyclic Al-O-P clusters; the role of OH...Cl contacts is emphasized.     

Trapping parameters and kinetics in CaS: Ce,Cl luminophor

By means of thermally stimulated luminescence (TL) technique the trapping parameters and order of the kinetics in TL process in the CaS: Ce, Cl luminophor are investigated. In the temperature range 300–450 K, two glow-peaks are observed showing the presence of two group of traps in this luminophor whose trap-depths are 0.66 ± 0.16 eV and 1.13 ± 0.11 eV respectively as determined by three different methods. The order of the kinetics in TL processes in this luminophor comes out to be first order for the first group and second-order for the second group of traps.     

Study of the Cl(He,p)Ar reaction

Angular distributions of protons from the ³⁵Cl(³He, p)³⁷Ar reaction have been measured at bombarding energies between 9 and 14 MeV. The 14 MeV data are compared with DWBA calculations based on various sets of shell-model wave functions.     

(Zn,Cd)S：Cu,Cl发光材料的热释发光

在ZnS中分别掺杂质量分数为5%、7%、10%、15%、20%的CdS,得到一系列(Zn,Cd)S:Cu,Cl粉末电致发光材料样品。测量样品材料的热释发光曲线,发现五个样品在温度-180～-20℃范围内均有两个明显的热释发光峰。CdS含量的变化对材料中陷阱的种类和陷阱深度没有明显的影响,两个峰值温度在-150℃和-50℃附近。Cd离子的掺入改变了材料较深陷阱中载流子的浓度,随着CdS量的增加,使得在-50℃的热释发光峰的相对强度增大。通过测量样品的发光光谱和发光亮度,发现随着CdS含量的增加,样品材料的发射光谱向长波方向移动,发光亮度呈下降的趋势。