Levels and transitions in126Te

The decay of¹²⁶Sb to¹²⁶Te is studied by use of Ge(Li) detectors in singles and coincidence arrangements. The gamma-gamma directional correlations of six cascades are measured. A level scheme is constructed where all transitions observed are located. The characteristics of several of the levels are assigned, on basis of the logft values deduced and the directional correlation results. Mixing ratios are deduced for three transitions. From the comparison of the relative intensities ofE1 andE2 transitions depopulating the same levels, threeE1 transitions are concluded to be strongly retarded.     

Gamma-gamma angular correlations in125Te

Angular correlation measurements of the γ transitions coincident with 35.5 keV in¹²⁵Te were carried out with Ge(Li)-Si(Li) detectors. Mixing ratios for some of the transitions were determined.     

Beta decay of 125Sb and level structures in 125Te

The decay of 2.76y ¹²⁵Sb to levels of ¹²⁵Te has been studied using an HPGe detector for gamma-ray and a mini orange electron spectrometer for conversion electron measurements. We identify 38 transitions in this decay, including 13 gamma rays and 4 conversion electron lines being reported for the first time. New results also include E1 multipolarity assignments to 3 newly observed transitions and M-shell conversion coefficient for the 109 keV M4 transition. A revised ¹²⁵Te level scheme is constructed using Ritz combination principle. While confirming the existence of 10 well established levels below 700 keV excitation, we introduce 3 other levels at 402.0, 538.6 and 652.9 keV. Interpretation of the observed levels in terms of various theoretical approaches is briefly discussed. The newly introduced 538.6 keV (1/2⁺) and 652.9 keV (3/2⁺) levels are seen as the two missing members of the (s _1/2 ⊗ 2⁺) and (d _3/2 ⊗ 2⁺) sextuplet in the quasiparticle-phonon coupling scheme.     

Multipole mixing ratios of transitions in Te

Gamma-gamma directional correlation measurements were made on nine transitions in ¹²⁴Te with a NaI(Tl)-Ge(Li) detector arrangement and multichannel analysis. The multipole mixing ratios obtained were δ(646) = 0.000±0.001, δ(714) = 1.5_−0.3^+0.6, δ(723) = −3.3±0.2, δ(1437) = 3.7_−2.0^+2.7, δ(1489) = −3.4_−1.5^+0.9, δ(968) = −0.03_−0.05^+0.06, δ(1368) = −0.045±0.090, δ(1045) = 0.041_−0.041^+0.047, δ(1691) = −0.02±0.01, and δ(2091) = 0.00_−0.03^+0.02. The first δ is M3/E2, the next three are E2/M1, and the last five are M2/E1. The retardation (a factor of approximately 50) of the crossover to cascade transitions from the 2039 keV, third 2⁺ level to the second and first 2⁺ levels is essentially the same for both the M1 and E2 components. In addition, spin and parity assignments of 2⁺ were made for the 2039 and 2092 keV levels.     

Subbarrier conversion in 125Te45+

We discuss the process of resonant subbarrier internal conversion of γ rays, where the converted electron is transferred to one of the atomic orbitals. For the first time we study how this process is affected by residual interactions: the splitting of the atomic terms in the total angular momentum of the atom, configuration mixing, and the magnetic interaction between the electrons of the atom. The calculations are done by the relativistic multiconfiguration Dirac-Fock method with allowance for the Breit interaction for the M1 transition with an energy of 35 492 eV in multiply charged ions of ¹²⁵Te. We show that allowing for the residual interaction is obligatory if we want to calculate the conversion rate in the vicinity of a resonance correctly. Zh. éksp. Teor. Fiz. 116, 1565–1574 (November 1999)     

Anomalous decay of 125m Te

An answer is given to the comment on my previous work devoted to studying anomalies in the decay of the ^125m Te isotope.     

Levels and transitions in136Ba

Excited states of¹³⁶Ba are studied in the beta decay of¹³⁶Cs. The gamma spectrum is measured with high-resolution and coincidence techniques. Several new transitions are suggested to be connected with two recently reported levels. Gamma-gamma directional correlations are performed in an attempt to determine the characteristics of these levels, and in order to determine mixing ratios. The lifetime of the 2207.5 keV state is remeasured, and the lifetime of the 2140.5 keV state is measured for the first time.     

Magnetic moment measurement in125Te by IPAC

The magnetic moment of the 35.5 keV (3/2⁺) excited state in¹²⁵Te was measured in an external magnetic field. The value obtained μ=0.57 ± 0.07μ _N agrees with Mössbauer determinations and Kisslinger-Sorensen calculations.     

Dynamics of125Te in transition metal ditellurides

The¹²⁵Te Mössbauer effect in the transition metal ditellurides NiTe₂, FeTe₂, and MnTe₂ was studied at atmospheric pressure between 78 and 297 K and a pressure of 7 GPa (78 or 297 K). The determined Debye temperatures are related to the crystal structure and electronic state of Te. The pressure-induced changes in the hyperfine interaction parameters are discussed in terms of charge transfer and structure type.     

Gyromagnetic ratios of excited states in 123, 125Te

The results of integral precession measurements are reported for $\text{3}\text{2}{}^{\mathrm{+}}$ and $\text{5}\text{2}{}^{\mathrm{+}}$ excited states in ^123,125Te. The measurements were made using the ion implantation perturbed angular correlation technique by recoiling the excited nuclei into polarized iron. The measured mean lifetimes and g-factors are: ${}^{123}\text{Te (440 keV,}\text{3}\text{2}{}^{\mathrm{+}}\text{) τ = 39±4 ps, g = 0.34 ± 0.06}$; $\text{(505 keV,}\text{5}\text{2}{}^{\mathrm{+}}\text{) τ = 26±3 ps, g = 0.04±0.025}$; and ${}^{125}\text{Te(443 keV,}\text{3}\text{2}{}^{\mathrm{+}}\text{) ρ = 27±3.3 ps, g = 0.39±0.06}$; $\text{(464 keV,}\text{5}\text{2}{}^{\mathrm{+}}\text{) g = 0.12±0.04}$. The results are compared with theoretical predictions.     

Thermodynamic parameters of diffuse phase transitions in Ag2Te

A differential thermal analysis in vacuum and studies of the coefficients of electrical conductivity and thermal conductivity, and of the thermal emf are made in Ag₂Te in the neighborhood of the structural phase transition. It is shown that these data can be used to calculate the switching factor L(T), determine the region in which the phases coexist within the transition, and calculate the thermodynamic parameters. Prior to and after the main phase transition, additional displacement transitions are observed. It is found that the phase transition takes place roughly according to the scheme α _{385 K}→α′_{405 K}→β′_{420 K}→β _{440 K}. The specific heat C _p, changes in entropy ΔS and transition enthalpy ΔH, as well as the minimum phase fluctuation volume V, and the heat Q of the phase transition are determined. It is shown that excesses of Te and Ag have almost no effect on the transition temperatures T ₀, but have a substantial effect on the thermodynamic parameters. Fiz. Tverd. Tela (St. Petersburg) 40, 1693–1697 (September 1998)     

125Te NMR tomography of [Re6] cluster in Re6Te15 and related cluster compounds

The static and magic angle spinning NMR solid-state spectra of Re6Te15 and a series of Re(6)-Te cluster compounds demonstrate the positive and negative 125Te NMR chemical shifts indicating that the [Re6] cluster distorts strongly magnetic field at the neighboring Te sites. The local magnetic field is decreased at the facial tellurium sites (Teface) and enhanced at the apexial tellurium sites (Teapex). The facial and sagittal sections of the Re(6)-Te clusters were reconstructed from analysis of Teface and Teapex NMR spectra, respectively.     

Calculation of 121Sb and 125Te Mössbauer Spectra

We propose an alternative approach for the analysis of the Mössbauer spectra of complex crystalline materials when the determination of the Mössbauer parameters from the only experimental data fails. This approach is based on first principle calculations of the electron density and electric field gradients at the nucleus based on the linearized augmented plane wave method. Results are given for tellurium and antimony compounds.

     

125m Te (109.3 keV) stimulated emission and gamma lasers

Summary Proceeding from the drastic discrepancy between experimental data and theory, we show (contrary to other authors) that the relations between the Einstein's coefficients are true for transitions from any of the excited levels and theground state of the quantum system only. The relations connecting those coefficients are derived for transitions betweenany two states; the corresponding cross-sections are calculated and it is shown (contrary to other authors) that the stimulated emission cross-section may be large enough for the creation of gamma lasers. The new relation for Einstein's coefficients (and the corresponding cross-sections) are fundamentally different from those known so far (74 years after Einstein). The results are compared with experiment and the coincidence is very good. These investigations can lead to progress in the study of physical processes in star atmospheres. The author of this paper has agreed to not receive the proofs for correction.     

Levels in124Te populated in the decay of124Sb

The levels in¹²⁴Te have been investigated by studying the gamma rays emitted following the decay of 60d¹²⁴Sb. Gamma-gamma coincidence spectra have been taken with gates set at 603, 646, 709, 714 and 723 keV gamma rays by using 105 cm³ Ge(Li)-110 cm³ HPGe coincidence system. 69 gamma rays have been observed and nine of them are reported for the first time. Four new levels in¹²⁴Te at 2512, 2550.2, 2808 and 2814.5 keV are proposed. Levels reported in literatures at 2412 and 2733 keV are excluded from the level scheme of¹²⁴Te based on the present study. The experimentally determined energy spectrum of low-lying positive parity states, B(E2) ratios and electric quadrupole moment of the first excited state are compared with the IBM-1 predictions.     

Collective polynuclear superradiance rather thanstimulated emission of Mössbauer radiation from125m2Te and 123m2Te

Acts attributed to single-particle stimulated emission, ^125m2Te(γ,2γ)^125m1Te, had been observed previously in a Be^125m2Te sample as a variation of the line intensity at Eγ=109.27 keV and by the appearance of a line of double energy at E_2γ=218.54 keV. This effect occurred when the sample temperature, T was lowered from 300 to 4 K. In the present work, the first observation is reported of stimulated emission events in the reaction ^123m2Te(γ,2γ)^123m1Te which were registered from a Mg₃ ^123m2TeO⁶ sample when cooled in a similar fashion. It is shown here that the mechanism of these experimentally observed events is polynuclear superradiance rather than a single-particle stimulated emission of Mössbauer radiation as earlier suggested.     

Levels and transitions in182W following the decay of182Ta

Zeitschrift für Physik A Hadrons and nuclei - The energy level scheme of182W has been established from γ — γ coincidence studies following the β decay of182Ta. A Dual...