Te Core Research Articles

Bis(μ2-phenyltellurolato)bis(phenyltellurolato)tetra-μ3-tellurido-hexakis(triphenylphosphine)hexapalladium(II) benzene nonasolvate

The centrosymmetric title complex, [Pd6(C6H5Te)4Te4(C18H15P)6]·9C6H6, contains two Pd3Te2 cores that are joined into a cyclic hexa­nuclear complex by two bridging PhTe− groups. Each PdII atom is coordinated by one triphenyl­phosphine ligand, one phenyl­tellurolate mol­ecule and two telluride ligands: two of the PhTe− ligands act as terminal ligands and two as bridging ligands. The three distinct PdII atoms each show a slightly distorted PdPTe3 square-planar coordination. The asymmetric unit also contains four and a half benzene solvent mol­ecules. Two of the benzene mol­ecules are disordered: one mol­ecule is distributed over two positions with site-occupancy factors of 0.529 (7) and 0.471 (7), while the other occupies two orientations about a centre of symmetry.

Job Analysis of Records Managers based on the AHP Method

This study started from recognizing the problem that neither the identity nor the role of records managers is clarified enough. Therefore, this study identifies the function of the records managers and how it should be carried. The method of functional analysis was used to collect information, and then the AHP method to analyze te core functions of the records managers. As a result, core functions were identified as follows: records management policy making, education, production control, records schedule management, collecting, transferring, description, appraisal, de-accessioning, records center management, disclosure, perusal service, and records management system. Therefore, this study presents that identity and role of the records managers as well as the priorities of the job.

Effect of Copassivation of Cl and Cu on CdTe Grain Boundaries

Using a first-principles method, we investigate the structural and electronic properties of grain boundaries (GBs) in polycrystalline CdTe and the effects of copassivation of elements with far distinct electronegativities. Of the two types of GBs studied in this Letter, we find that the Cd core is less harmful to the carrier transport, but is difficult to passivate with impurities such as Cl and Cu, whereas the Te core creates a high defect density below the conduction band minimum, but all these levels can be removed by copassivation of Cl and Cu. Our analysis indicates that for most polycrystalline systems copassivation or multipassivation is required to passivate the GBs.

Ag ∕ Pb Te ( 111 ) interface behavior studied by photoemission spectroscopy

We performed investigations on the formation of Ag∕PbTe(111) interface by using photoemission spectroscopy. Upon initial Ag deposition, both Pb 4f and Te 3d core levels and the valence-band edge showed shifts to high binding energy, from which the band bending at Ag∕PbTe(111) is determined to be 0.13eV. Upon further Ag deposition, new components appear in Pb and Te core levels, with intensities remaining constant even at higher Ag thickness. The experimental results, together with ab initio calculation, indicate that both Te and Pb outdiffuse to the outmost surface, and a single Te-terminated Pb–Te bilayer is formed over Ag film on PbTe(111).

A direct measurement of g-factors in II–VI and III–V core–shell nanocrystals

This study describes a direct measurement of spectroscopic g-factors of photo-generated carriers in InP/ZnS and HgTe/Hg x Cd 1− x Te(S) core–shell nanocrystals. The g-factor of trapped electrons and their spin-lattice versus radiative relaxation ratio ( T 1/ τ) were measured by the use of continuous-wave and time-resolved optically detected magnetic resonance (ODMR) spectroscopy. The g-factors of excitons and donor–hole pairs were derived by the use of field-induced circular-polarized photoluminescence (CP-PL) spectroscopy. The combined information enabled to determine the g-factors of the individual band-edge electrons and holes. The results suggested an increase of the g-factor of the exciton and conduction electron with a decrease of the nanocrystal size.

On the Neutron Method of Transmutation of Nuclear Wastes

Accumulation of radioactive nuclear wastes all over the world is among the most severe ecological problems that must be solved without delay. In this regard, of great interest is the neutron method of transmutation of nuclear wastes using neutron fluxes from reactors. The neutron method of fusion of new elements is based on the successive capture of neutrons by the initial cores. The cores that absorbed neutrons undergo β-decay. As a result, new cores with masses and charges exceeding the initial ones are created. Interest in the neutron method arose in 1966, when a group of American physicists from the Los-Alamos National Laboratory performed underground experiments on thermonuclear fusion of transuranium elements in Nevada [1]. U and Am targets were irradiated by neutron fluxes produced during explosions of thermonuclear charges. The heaviest transuranium element they obtained was Fm. They tried to detect Fm and Md elements among the irradiation products, but did not succeeded. This failure was explained in 1980, when American physicists from the Los-Alamos and Livermore National Laboratories succeeded in fusion of Fm in the reaction Fm(t, p) Fm. The Fm half-life for spontaneous fission was T = 1.5 s. This is almost 10 times less than Т = 131 year for Fm [2]. Analogous decrease in Т with increasing number of neutrons in a fissionable nucleus was revealed in fusion of Fm in the reaction Fm(d, p) Fm [3]. For Fm, Т = 380 ± 60 μs, which is almost 10 times less than Т = 160 min for Fm [4]. The authors of these experiments explained this sharp destabilization of heavy fermium isotopes undergoing spontaneous fission by the shell structure of fragments. The latter become more and more close to the doubly magic nucleus Sn with Z = 50 and N = 82 as the number of neutrons in the fissionable nucleus increases. It should be noted that fragments of the heavy Fm isotopes – magic and nearly margic Sn–Sn isotopes – are weakly active cores. After a series of β-decays with half-lives from 2.2 min to 77.4 h they are transformed into stable Te or Xe cores [5]. Thus, the magic character of fragments of heavy fermium isotopes was a reason for their rapid spontaneous decay. Therefore, new transuranium elements with Z > 100 were not fused by the neutron method. The mendelevium element with Z = 101 was first discovered in USA in 1955 in the course of the nuclear reaction Еs(α, n) Md. The next elements with Z > 101 were fused in nuclear reactions with accelerated heavy ions [6]. Unsuccessful attempts to fuse the far transuranium elements [1] were caused by the unique obstacle – the predisposition of heavy fermium isotopes to spontaneous fission. This property could be useful for transmutation of nuclear wastes. There are grounds to believe that cores of radioactive wastes, including actinides and fission fragments, will gradually approach the fermium precipice in the process of neutron absorption and will end their existence in the form of weakly active Sn isotopes. These isotopes must be removed from the mixture of cores. Otherwise, the Sn isotopes can also start to absorb neutrons, new radionuclides will be accumulated, and the process as a whole will be reminiscent of the Sisyphys work. This work can be useful for the experts evaluating perspectives for the neutron method of transmutation of radioactive wastes.

Band structures in 116I

The band structures of the doubly-odd nucleus 116I have been studied by using in-beam γ-ray spectroscopy with the 103Rh( 16O, 3n) 116I reaction at an energy of E lab=80 MeV. The beam was provided by the 12UD tandem accelerator at the University of Tsukuba. Absolute excitation energies for the observed collective bands except for a band based on the π(h 11/2) ν(g 7/2) configuration have been definitely determined. The positive-parity rotational band based on the π(h 11/2) ν(h 11/2) configuration is built on the 8 + level at 874.3 keV and exhibits a spin inversion below I=14ℏ. A new vibration-like band built on the 8 − level at 468.5 keV has been identified and can be interpreted as resulting from the π(g 7/2) ν(h 11/2) configuration coupled to the Te core vibration. A negative-parity band built on the 14 − level at 2547.6 keV shows a vibration-like structure and terminates its collectivity at the 24 − level at 6215.0 keV. The total Routhian surface calculations suggest a noncollective oblate state with β 2=0.182 and γ=60° based on a fully aligned six-quasiparticle, π[h 11/2(g 7/2) 2] ν[g 7/2(h 11/2) 2], configuration for this 24 − level. The excitation energy of the 7 − isomer with T 1/2=3.27 μs was found to be at 430.4 keV.

Synthesis, Structure, and Properties of Molybdenum and Tungsten Cyano Complexes with Cuboidal M(4)(&mgr;(3)-E)(4) (M = Mo, W; E = S, Se, Te) Cores.

Four new tungsten and molybdenum cyano complexes of formula KCs(5)[W(4)S(4)(CN)(12)].CH(3)OH.2H(2)O (1), K(6)[W(4)Se(4)(CN)(12)].6H(2)O (2), K(6)[W(4)Te(4)(CN)(12)].5H(2)O (3), and K(7)[Mo(4)Te(4)(CN)(12)].12H(2)O (5) have been prepared by high-temperature 430-450 degrees C reaction of the polymeric chain compounds {W(3)S(7)Br(4)}(x)(), {W(3)Se(7)Br(4)}(x)(), {Mo(3)Te(7)I(4)}(x)() and solid-state WTe(2) with KCN, and crystallization from aqueous solutions. In addition Cs(6)[Mo(4)Te(4)(CN)(12)].2H(2)O (4) has been prepared by oxidation of 5 with bromine water. The molecular structures have been investigated by X-ray crystallography. Mixed-valence (3.5) compounds 1-4 are diamagnetic. Mixed-valence (3.25) compound 5 is paramagnetic (&mgr; = 2.03 &mgr;(B) at 77 K). In addition to the structural data for these complexes IR and UV-vis spectroscopy have been used to characterize the complexes. Cyclic-voltammetry data have shown that M(4)E(4)(n)()(+) (M = Mo, W; E = S, Se, Te) cubes are capable of existing in three oxidation states ranging from the most oxidized (n = 6; 10 electrons) to the most reduced electron-precise (n = 4; 12 electrons). The (77)Se, (125)Te, and (183)W NMR spectra of the cubes (1-3) demonstrate unambiguously the unaltered environments of the W and E atoms in aqueous solution.

Chalcogenide-bridged cuboidal clusters with M4Q4 (M = Mo, W; Q = S, Se, Te) cores

Cuboidal cluster complexes having M4Q4 cores made up of transition and main group metals (M), and non-metallic e.g. chalcogenide elements (Q), constitute a rapidly expanding area of inorganic chemistry. Extensive preparation, structural and reactivity studies have been carried out on the Group 6 metals (M = Mo, W) and chalcogenide (Q = S, Se, Te) clusters, and are the main focus of this perspective. The aqueous solution chemistry provides an important reference point in considering redox and other relevant properties.

Electronic structures and local atomic configurations in amorphous GeSe and GeTe

The valence- and conduction-band electronic densities of states (DOSs) in amorphous (a-) GeSe and GeTe were investigated by means of ultraviolet photoemission and inverse-photoemission spectroscopy (UPS and IPES), respectively. The UPS spectra for both a-GeSe and a-GeTe are very similar to those obtained in previous experiments; a distinct peak appears near the top of the valence band. The IPES spectra for both a-GeSe and a-GeTe corrected by subtracting the background exclude the possibility of a structure with 3(Ge):3(chalcogen) coordination if one compares them with the theoretical DOS calculated by O'Reilly, Robertson and Kelly. The corrected IPES spectrum for a-GeSe resembles the broadened theoretical DOS for chemically ordered 4(Ge):2(Se) structure, whereas that for a-GeTe resembles the theoretical DOS for randomly bonded 4(Ge):2(Te) structure. The characters of the conduction-band DOSs for a-GeSe and a-GeTe were also examined by means of soft-x-ray core absorption spectroscopy. The Ge and Se core absorption spectra of a-GeSe are very similar to those of a-, and were discussed using a simple bonding model with a 4(Ge):2(Se) local configuration. The Ge and Te core absorption spectra of a-GeTe were also discussed using a simple local bonding model. All of the present measurements indicate that both a-GeSe and a-GeTe have structures with 4(Ge):2(chalcogen) coordination.

Fabry-Perot imaging of molecular hydrogen emission on Orion-KL region

view Abstract Citations (21) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Fabry-Perot Imaging of Molecular Hydrogen Emission in Orion-KL Region Sugai, Hajime ; Usuda, Tomonori ; Kataza, Hirokazu ; Tanaka, Masuo ; Inoue, Motoko Y. ; Takami, Hideki ; Aoki, Tetsuo ; Hiromoto, Norishisa ; Kawavata, Hironobu Abstract A continuum-subtracted image of the H2 nu = 1 goes to 0 S(1) line covering the central 4 min square portion of the Orion-KL region, has been obtained using a wide-field Fabry-Perot imager at the Communication Research Laboratoy 1.5 m telescope. Nine H2 peaks (including four newly identified) are found in te core, as well as a curved, bridgelike structure that enroaches on the inner edge of the disk structure observed in CS (J = 1 goes to 0) emission. This existence of the bridge indicates that the outflow from IRc2 occurs not only toward the bipolar axis but also toward the disk, and suggests channeling by the disk of a more or less isotropics flow from IRc2 into a bipolar flow. Outside the core, where finger-like features of H2 emission are seen, we identify 43 hot H2 clumps. These are located along filamentary structures seen in CS (J = 1 goes to 0) maps and avoid peaks of CS intensity. The geometrical thickness of the hot H2 in these features is much smaller than their typical dimension. We conclude that the H2 emission from the clumps is radiated at the surface of the CS filaments, implying that outflow form IRc2 shocks the H2 at the surfaces. From comparison of polarization measurements of Burton et al. (1991) with the present meausrements, as well as from discussion of the energetics, we rule out the possibility that the H2 clumps are due to reflection. Publication: The Astrophysical Journal Pub Date: January 1994 DOI: 10.1086/173599 Bibcode: 1994ApJ...420..746S Keywords: Hydrogen Clouds; Interstellar Matter; Orion Nebula; Data Reduction; Emission Spectra; Fabry-Perot Spectrometers; Herbig-Haro Objects; Isotropic Media; Shock Waves; Astrophysics; ISM: INDIVIDUAL NAME: ORION NEBULA; ISM: JETS AND OUTFLOWS; ISM: MOLECULES; SHOCK WAVES full text sources ADS | data products SIMBAD (58)

Charge transfer and core-hole screening in PbTe.

An analysis of the Auger-parameter shifts between PbTe and the pure elements is shown to yield insight into mechanisms of core-hole screening and charge transfer in the ground state. A parametrized treatment of the Auger-parameter shifts in which the screening terms are treated in terms of a Jost-cavity model shows that the ground-state charge transfer in PbTe is less than 0.30e\ifmmode\pm\else\textpm\fi{}0.06e. It is shown that core holes are screened more efficiently on Pb sites than on Te sites in PbTe, and that Te core holes are screened more efficiently in pure Te than in PbTe.

Photoemission studies of the room-temperature Si/Hg1−xCdxTe, Si/HgTe, and Si/CdTe interfaces

The room-temperature interface between Si and Hg1−xCdxTe (x=0, 0.30, 0.39, 1.0) was investigated using the surface sensitive techniques of photoemission spectroscopy and low-energy electron spectroscopy (LEED). Elemental Si was electron beam evaporated onto atomically clean cleaved (110) surfaces in ultrahigh vacuum and the chemistry and morphology of the interface was monitored as a function of Si overlayer growth. The LEED pattern disappeared at ∼1 monolayer (ML) coverage Si for all substrates, indicating that the overlayer coverage was fairly uniform. At submonolayer Si coverages on the Hg containing alloys, the substrates exhibited Hg loss with Te coming out of the substrate into the overlayer. At moderate coverages (<6 ML), Te continued to come to the surface. Chemical shifts of the Si and Te core levels suggest that Te interacts with Si in the overlayer, with the possible formation of Si–Te phases in the overlayer. At thicker coverages of Si, Hg and Cd are seen to intermix within the Si overlayer, but stay away from the surface. For the Si/CdTe case, there is much less interaction between the Si overlayer and the substrate. Therefore Si appears to disrupt the surface of the Hg containing alloys much more than that of CdTe and hence the weaker Hg–Te bond in the lattice is seen to play a central role in dictating the surface chemistry and morphology in this alloy system. These findings have possible implications into Si-based passivation layers on HgCdTe.

Collective properties of the odd-mass I nuclei:I117,119,121

The high-spin states of /sup 117,119,121/I have been investigated by in-beam ..gamma..-ray spectroscopy via the /sup A/Sn(/sup 6/Li,3n)/sup A/+3I reactions to study the collective properties of the odd-mass I isotopes. A similar study of /sup 123,125,127/I is reported in the preceding paper. Two collective features have been observed: ..delta..J = 1 bands built on low-lying (9/2)/sup +/ proton-hole states and ..delta..J = 2 bands built on (11/2)/sup -/, (7/2)/sup +/, and (5/2)/sup +/ quasiproton states. The ..delta..J = 2 energy spacings for the (11/2)/sup -/ bands decrease significantly relative to those for the ground-state bands of the Te core nuclei as A decreases, but not for the (7/2)/sup +/ and (5/2)/sup +/ ..delta..J = 2 bands. This unexpected decrease can be explained in a generalized seniority scheme. The systematic properties of the ..delta..J = 2 bands for all of the odd-mass I isotopes are summarized. These collective properties are examined in terms of both the microscopic and phenomenological approaches. Pulsed-beam-..gamma.. measurements yielded mean lifetimes of tau = 17.5 +- 1.0, 41.5 +- 1.5, and 13.5 +- 0.5 ns for the (9/2)/sup +/ proton-hole states in /sup 117,119,121/I, respectively. These values imply hindrances of approx.10/sup 4/ relative to M1 Weisskopf estimatesmore » for the transitions to the (7/2)/sup +/ quasiproton states. A spin rotation measurement yielded a g factor for the (9/2)/sup +/ isomer in /sup 119/I of g = 1.21 +- 0.08. Another isomer with a mean life of tau = 13 +- 2 ..mu..s was observed at 2377 keV in /sup 121/I.« less

Collective properties of the odd-mass I nuclei:I123,125,127

The high-spin states of $^{123,125,127}\mathrm{I}$ have been investigated via the $^{A}\mathrm{Sn}(^{6}\mathrm{Li}, 3n)^{A+3}\mathrm{I}$ reactions to study the collective properties of the odd-mass I isotopes. In-beam measurements of $\ensuremath{\gamma}$-ray excitations, $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, $\ensuremath{\gamma}$-ray angular distributions, and pulsed beam-$\ensuremath{\gamma}$ timing were performed with Ge detectors to determine level energies, decay schemes, $\ensuremath{\gamma}$-ray multipolarities, ${J}^{\ensuremath{\pi}}$ assignments, and lifetime information. A similar study of the $^{117,119,121}\mathrm{I}$ isotopes is reported in the following paper. Two collective features have been identified in these odd-mass I nuclei. Systematic $\ensuremath{\Delta}J=1$ bands built on low-lying ${\frac{9}{2}}^{+}$ proton-hole (4p-1h) states were observed. The ${\frac{9}{2}}^{+}$ bandheads, that involve the excitation of a $1{g}_{\frac{9}{2}}$ proton across the $Z=50$ shell, drop to very low energies near the middle of the neutron shell. The properties of the ${\frac{9}{2}}^{+}$ proton-hole states for all of the odd-mass I isotopes are presented and related to the systematic information for the proton-hole states in the entire $Zg50$ transition region. Systematic $\ensuremath{\Delta}J=2$ bands built on ${\frac{11}{2}}^{\ensuremath{-}}$ ($1{h}_{\frac{11}{2}}$ quasiproton) states, on ${\frac{7}{2}}^{+}$ ($1{g}_{\frac{7}{2}}$ quasiproton) states, and on ${\frac{5}{2}}^{+}$ ($2{d}_{\frac{5}{2}}$ quasiproton) states were also observed. The $\ensuremath{\Delta}J=2$ band spacings generally follow the spacings of the Te-core ground-state bands with the exception of the ${\frac{11}{2}}^{\ensuremath{-}}$ $\ensuremath{\Delta}J=2$ bands, for which the spacings decrease significantly relative to those for the Te cores as $A$ decreases. These systematic properties are discussed in terms of several theoretical approaches to the onset of collectivity in transitional nuclei. An isomer at 2660 keV in $^{123}\mathrm{I}$ was observed to have a mean lifetime $\ensuremath{\tau}=38\ifmmode\pm\else\textpm\fi{}3$ ns.NUCLEAR REACTIONS $^{120\ensuremath{-}124}\mathrm{Sn}(^{6}\mathrm{Li}, 3n)^{123\ensuremath{-}127}\mathrm{I}$; measured $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, $\ensuremath{\gamma}(E, \ensuremath{\theta}, t)$; deduced level schemes in odd-mass $^{123\ensuremath{-}127}\mathrm{I}$, $\ensuremath{\gamma}$ multipolarities, ${J}^{\ensuremath{\pi}}$, ${T}_{\frac{1}{2}}$. Enriched targets, Ge(Li) detectors.

?J=1 band structures on ns-isomeric states in odd mass117, 119, 121Te nuclei

In117Te,119Te and121Te isomeric states withJ π=5/2+, 5/2+ and 7/2+ and half-lives of 19.1(9)ns, 2.2(2) ns and 86(6) ns, respectively, have been identified at low excitation energies using (α, 2n) reactions on enriched115–119Sn targets. Positive parityΔJ=1 bands built on these isomeric states have been observed up to 17/2+. The states are interpreted as members of rotational bands built on deformation driving 5/2+ [402] and 7/2+ [404] Nilsson orbitals which overcome theN=64 subshell gap. The irregular level spacings and electromagnetic properties of the bands are well explained in Coriolis calculations. The moment of inertia parameter as function of collective angular momentum has been derived from the doubly even Te cores. The hindrance of the band head deexcitation may be caused by shape fluctuations of these transitional nuclei.

Collective properties of A = 117−127 odd- A I nuclei

Systematic ΔJ = 2 bands have been observed on the d 5 2 , g 7 2 and h 11 2 quasi-proton states in A = 117−127 odd-I nuclei. The ΔJ = 2 energy spacings decrease (relative to the Te cores) as A decreases for the h 1 2 band but not for the others. Also ΔJ = 1 bands on unsually low-lying g 9 2 proton-hole states exist.

Effect of disorder on the unoccupied states of germanium telluride

The Te L1 and L3 X-ray absorption spectra for some GeTe compounds in amorphous and crystalline form are presented. No shifts of the Te core levels 2s and 2p3/2 were observed between the amorphous and crystalline phases or between the element and the compounds. The L3 but not the L1 spectra showed changes in structure about 5-10 eV above the Fermi level when amorphous GeTe crystallized. This is attributed to states about 6 eV above EF and it is concluded that these largely d-like states are more affected by the order-disorder transformation than the lower sp bands.

Electronic Displacement in Tellurium by Mechanical Strain

AbstractThe piezoelectric constants e11 and e14 of tellurium have been found by measurement to be 0.42 C m−2 and 0.17 C m−2. They are described by strain‐induced displacement of the electron distribution relative to the Te cores.