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  • 1
    Electronic Resource
    Electronic Resource
    Electron capture processes in optically excited In0.53Ga0.47As/InP quantum wells (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 933-935 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have performed picosecond time-resolved measurements on In0.53Ga0.47As/InP quantum wells with varying barrier thicknesses using 10 ps Nd:YAG excitation. For this excitation, holes and electrons are created in the In0.53Ga0.47As layers. Due to momentum conservation the Nd:YAG excitation accelerates the electrons above the InP barrier where they can diffuse but cannot recombine. By examining the rise time of the quantum well emission, we can show that for samples with thick barriers, the barrier geometry largely controls the dynamic properties of the carriers after Nd:YAG excitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101728
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  • 2
    Electronic Resource
    Electronic Resource
    A detailed study of strange particle production ine + e − annihilation at high energy (1985)
    Springer
    The European physical journal 27 (1985), S. 27-37 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Results onK 0 and Λ production ine + e − annihilation at c.m. energies of 14, 22 and 34 GeV are presented. The shape of theK 0 and Λ differential cross sections are very similar to each other and to those of π±,K ± and $$p(\bar p)$$ . Scaling violations are observed forK 0 production. We obtain a value for the probability to produce strange quark-antiquark pairs relative to that to produce up or down quark-antiquark pairs of 0.35±0.02±0.05. The value ofR h =σ(e + e -→hX)/σµµ is shown to rise steadily with c.m. energy for all particle species. At 34 GeV we find 1.48±0.05K 0 and 0.31±0.03 Λ per event. We have searched for possible Λ polarization. The production ofK 0's and Λ's in jets is examined as a function ofp T 2 and rapidity and compared to that of all charged particles; the yields in two and three jets are also investigated. Results are presented from events with two baryons $$(\Lambda ,\bar \Lambda ,por\bar p)$$ observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01642477
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  • 3
    Electronic Resource
    Electronic Resource
    The production and decay of Tau leptons ine + e − annihilation at PETRA energies (1985)
    Springer
    The European physical journal 26 (1985), S. 521-530 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have observed τ pair production at average CM energies of 13.9, 22.3, 34.5 and 43.1 GeV. The cross-sections are consistent with QED, the cut off parameters beingΛ +〉161 GeV andΛ −169 GeV (95% CL). The topological branching fraction of the τ to 1 charged particle,B 1, is 0.847±0.011 (stat) −0.013 +0.016 (syst) and no decays to 5 charged particles were observed resulting inB 5〈0.007 (95% CL). Within the 3 charged track final stateB(τ −→π − π + π − v)/(B(τ −→π − π + π − v)+B(τ −→π − π + π − π 0 v))=0.37 −0.20 +0.35
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01551794
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  • 4
    Electronic Resource
    Electronic Resource
    A study of 3-jet events ine + e − annihilation into hadrons at 34.6 GeV c.m. energy (1985)
    Springer
    The European physical journal 29 (1985), S. 29-40 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Three-jet events produced bye + e − annihilation into hadrons at 34.6 GeV c.m. energy were studied by comparing them with 2nd order QCD and two different models of fragmentation. The distribution of low energy particles in the 3-jet plane is found to be better described by the LUND color string model than by the independent jet model. The opposite is true for more energetic particles flowing between the 3 jets. The average transverse momenta in jets can be described with values of σ q between 350 and 500 MeV/c for the gluon jet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01571375
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  • 5
    Electronic Resource
    Electronic Resource
    Wafer and epilayer improvement for integrated optics devices on InP: the ESPRIT project 2518 (1991)
    Springer
    Optical and quantum electronics 23 (1991), S. 391-404 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Ga x In1−x As y P1−y alloys lattice matched to InP substrates are currently used to fabricate optoelectronic and integrated optics devices. To achieve devices with high performances and high fabrication yield, the uniformity and reproducibility of the Ga x In1−x As y P1−y epitaxial layers (composition, thickness, doping, etc.) have become key parameters. These problems have been addressed in the frame of ESPRIT project 2518 and are presented in this paper. Several aspects have been considered starting from the optimization of InP substrates, the MOVPE growth of uniform GalnAsP layers, the material characterization to the validation of material uniformity on passive optical waveguides. Both scanning photoluminescence analysis and waveguide losses measurements performed on 2 inch wafers with a high lateral resolution have shown that high quality uniform GalnAsP layers can be obtained reproducibly on 2″ InP substrates using a commercially available LP-MOCVD growth process. In particular, more than 60% of 36 mm long, 3μm wide and 100μm spaced rib waveguides exhibit losses below 0.8dBcm−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619612
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  • 6
    Electronic Resource
    Electronic Resource
    Zur Kristallchemie einiger Alkalithiomanganate und-zinkate. Mit einer Bemerkung zum ThCr2Si2-TypProfessor Rudolf Hoppe zum 65. Geburtstage am 29. Oktober 1987 gewidmet (1987)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 553 (1987), S. 248-260 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Chemistry of Some Alkali Thiomanganates and -zincates. With a Remark on the ThCr2Si2-TypeNew quaternary sulfides ALiMS2 (A ≙ K, Rb, Cs and M ≙ Mn, Zn) were synthesized by a reaction of alkali carbonates with manganese and zinc, respectively, in a stream of H2S at 800°C. Single crystal X-ray investigations revealed the structures of KLiMnS2 and KLiZnS2.All compounds are isotypic and crystallize in the BaZn2P2-structure type. The atomic arrangements are treated as nine spheres close packings of sulfur atoms filled with cations. Criteria are given to distinguish the BaZn2P2-structure type from the ThCr2Si2-structure type.
    Notes: Erstmals dargestellt wurden die quaternären Sulfide ALiMS2 (A ≙ K, Rb, Cs und M ≙ Mn, Zn) durch Umsetzung der Alkalicarbonate mit Mangan bzw. Zink im H2S-Strom bei 800°C. Die Strukturen von KLiMnS2 und KLiZnS2 wurden an Einkristallen bestimmt.Alle Verbindungen sind isotyp und kristallisieren im BaZn2P2-Typ. Die Strukturen werden diskutiert als mit Kationen aufgefüllte Neunerkugelpackungen der Schwefelatome. Es werden Kriterien angegeben, die eine Unterscheidung der Strukturtypen BaZn2P2 und ThCr2Si2 erlauben.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19875531030
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  • 7
    Electronic Resource
    Electronic Resource
    Cs4Re6S13 und Cs4Re6S13,5 - zwei Verbindungen mit [Re6S8]-Baueinheiten in geringfügig variierten GerüststrukturenProfessor Dirk Reinen zum 60. Geburtstage gewidmet (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 587 (1990), S. 91-102 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cs4Re6S13 and Cs4Re6S13.5  -  Two Compounds with [Re6S8] Clusters Slightly Differing as to their Framework StructuresCs4Re6S13 was synthesized by the reaction of cesium carbonate with rhenium at 800°C in an argon atmosphere charged with sulphur. The preparation of Cs4Re6S13.5 succeeded by an analogous procedure using a stream of H2S.Structural investigations on single crystals revealed atomic arrangements in which [Re6S8] clusters are linked threedimensionally by Sn2- bridges. In the compound Cs4Re6S13 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)4/2 the rhenium atoms of adjacent Re6-octahedra are connected by sulphide and disulphide bridges in a ratio of 1:2. In the compound Cs4Re6S13.5 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)3/2(S3)1/2 one disulphide bridge is replaced by one trisulphide bridge.The nearly regular Re6-octahedra correspond with a diamagnetic 24-electron configuration.
    Notes: Cs4Re6S13 wurde durch Umsetzung von Caesiumcarbonat mit Rhenium in einem mit Schwefel beladenen Argonstrom bei 800°C erhalten. Cs4Re6S13,5 konnte nach einem analogen Verfahren im Schwefelwasserstoffstrom synthetisiert werden.Strukturuntersuchungen an Einkristallen führten zu Atomanordnungen, in denen [Re6S8]-Baueinheiten über Sn2--Brücken dreidimensional zu Gerüststrukturen verknüpft sind. Im Cs4Re6S13 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)4/2 werden die Rheniumatome benachbarter Re6-Oktaeder über Sulfid- und Disulfidbrücken im Verhältnis 1:2 miteinander verbunden, im Cs4Re6S13,5 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)3/2(S3)1/2 ist eine Disulfidbrücke durch eine Trisulfidbrücke ersetzt.Die nahezu regulären Re6-Oktaeder sind in Übereinstimmung mit dem unmagnetischen 24-Valenzelektronenzustand.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19905870111
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  • 8
    Electronic Resource
    Electronic Resource
    Schichtstrukturen ternärer Chalkogenide A2M3X4 (A ≙ K, Rb, Cs; M ≙ Ni, Pd, Pt; X ≙ S, Se)Professor Hanskarl Müller-Buschbaum zum 60. Geburtstage gewidmet (1991)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 597 (1991), S. 27-32 
    Details
    ISSN: 0044-2313
    Keywords: Ternary chalcogenides A2M3X4 (A ≙ alkali metal; M ≙ Ni, Pt, Pd; X ≙ S, Se) crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Layered Structures of Ternary Chalcogenides A2M3X4 (A ≙ K, Rb, Cs; M ≙ Ni, Pd, Pt; X ≙ S, Se)The ternary chalcogenides A2M3X4 have been prepared by fusion reactions of alkali carbonates with metals M ≙ Ni, Pd or Pt and the chalcogens X ≙ S or Se. Alternatively, the chalcogenides could be synthesized from alkali carbonates and M in a stream of hydrogen charged with chalcogen. X-ray investigations on powdered samples and single crystals reveal layered structures in which neutral A2M3X4-slabs from stacking variants.
    Notes: Die Synthese ternärer Chalkogenide A2M3X4 gelang über Schmelzreaktionen durch Umsetzungen von Alkalimetallcarbonaten mit den Metallen M ≙ Ni, Pd oder Pt und den Chalkogenen X ≙ S oder Se oder über eine Reaktion der beiden erstgenannten Komponenten in einem mit Chalkogen beladenen Wasserstoffstrom.Röntgenographische Untersuchungen an pulverförmigen Proben sowie an Einkristallen führten zu Schichtstrukturen, in denen neutrale A2M3X4-Schichtpakete Stapelvarianten erzeugen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19915970105
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  • 9
    Electronic Resource
    Electronic Resource
    Neue Alkalimetallchromchalkogenide und ihre StruktursystematikProfessor Hartmut Bärnighausen zum 60. Geburtstage gewidmet (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 243-252 
    Details
    ISSN: 0044-2313
    Keywords: Alkali metal chromium chalcogenides ; crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Alkali Metal Chromium Chalcogenides and their Structural ClassificationThe compounds RbCr3S5, K3Cr11S18, RbCr5Se8 and CsCr5Se8 could be obtained in the form of wellshaped crystals via fusion reactions of the alkali metal carbonates with chromium and the corresponding chalcogen. The compounds crystallize in the monoclinic space groups C2/m (RbCr3S5: a = 19.372(3) Å, b = 3.498(1) Å, c = 12.119(2) Å, β = 122.78(1)°, Z = 4; K3Cr11S18: a = 41.876(3) Å, b = 3.463(1) Å, c = 16.315(3) Å, β = 150.07(1)°, Z = 2; RbCr5Se8: a = 18.737(2) Å, b = 3.623(1) Å; c = 9.016(1) Å, β = 104.65(1)°, Z = 2; CsCr5Se8: a = 18.795(2) Å, b = 3.637(1) Å, c = 9.104(1) Å, β = 104.52(1)°, Z = 2).We propose a structure classification from group-subgroup-relations.MAPLE calculations reveal that the reactions of the binary chalcogenides to yield the ternary compounds are exothermic in each case and are dependent on the chromium/alkali metal ratio in the ternary chalcogenides.
    Notes: Durch Umsetzungen der Alkalimetallcarbonate mit Chrom und dem entsprechenden Chalkogen in der Schmelze konnten die Verbindungen RbCr3S5, K3Cr11S18, RbCr5Se8 und CsCr5Se8 als gut ausgebildete Kristalle erhalten werden. Die Verbindungen kristallisieren monoklin im Raumgruppentyp C2/m (RbCr3S5: a = 19,372(3) Å, b = 3,498(1) Å, c = 12,119(2) Å, β = 122,78(1)°, Z = 4; K3Cr11S18: a = 41,876(3) Å, b = 3,463(1) Å, c = 16,315(3) Å, β = 150,07(1)°, Z = 2; RbCr5Se8: a = 18,737(2) Å, b = 3,623(1) Å; c = 9,016(1) Å, β = 104,65(1)°, Z = 2; CsCr5Se8: a = 18,795(2) Å, b = 3,637(1) Å, c = 9,104(1) Å, β = 104,52(1)°, Z = 2).Über Gruppe-Untergruppe-Beziehungen wird eine Struktursystematik vorgeschlagen.MAPLE-Rechnungen zeigen, daß die Reaktionen der binären Chalkogenide zu den ternären Verbindungen jeweils exotherm sind und vom Verhältnis Chrom/Alkalimetall in den ternären Chalkogeniden abhängen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190205
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  • 10
    Electronic Resource
    Electronic Resource
    Alkalimetallrheniumsulfide und -selenide mit [Re6X8]-Baueinheiten (1985)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 525 (1985), S. 41-53 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkali Metal Rhenium Sulphides and Selenides Containing [Re6X8] ClustersThe sulphides Rb4Re6S13 and Rb2K2Re6S13 were synthesized by the reaction of alkali metal carbonates with rhenium in a stream of H2S at 800°C. The preparation of the selenides Cs4Re6Se13,-Rb4Re6Se12, and K4Re6Se12 succeeded when a hydrogen atmosphere charged with selenium was used. By combining both reaction methods we obtained mixed crystals of the composition Cs4Re6S9.45Se3.55.Structural investigations on single crystals revealed atomic arrangements in which [Re6X8] clusters are linked threedimensionally by X and X2 bridges. In the A4Re6X12-type a {[Re6X8]X4/2(X2)2/2}4- framework is found whereas the corresponding notation for the A4Re6X12-type is {[Re6X8]X2/2(X2)4/2}4-. The dependence of the respective type of framework on the size of the alkali metal ions will be discussed.The diamagnetic behaviour, which was measured in the temperature range between 3.8 and 300 K corresponds with the existence of nearly regular Re6-octahedra with a 24-electron configuration.
    Notes: Die Sulfide Rb4Re6S13 und Rb2K2Re6S13 wurden durch Umsetzungen von Alkalimetallcarbonaten mit Rhenium im Schwefelwasserstoffstrom bei 800°C erhalten. Die Selenide Cs4Re6Se13, Rb4Re6Se12 und K4Re6Se12 entstehen, wenn bei entsprechender Reaktionsführung ein mit Selen beladener Wasserstoffstrom eingesetzt wurde. Durch Kombination beider Verfahren erhielten wir Mischkristalle der Zusammensetzung Cs4Re6S9,45Se3,55.Strukturuntersuchungen an Einkristallen führten zu Atomanordnungen, in denen [Re6X8]-Baueinheiten über X- und X2-Brücken zu dreidimensionalen Gerüststrukturen verknüpft sind. Im A4Re6X12-Typ liegt ein {[Re6X8]X4/2(X2)2/2}4--, im A4Re6X13-Typ ein {[Re6X8]X2/2(X2)4/2}4--Gerüst vor. Die Abhängigkeit des jeweils gebildeten Gerüststrukturtyps von der Größe der eingelagerten Alkalimetallionen wird diskutiert.Der im Temperaturbereich zwischen 3,8 und 300 K gemessene Diamagnetismus stimmt mit der Annahme einer 24-Elektronenkonfiguration nahezu regulärer Re6-Oktaeder überein.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19855250607
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