Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 20 for “"Valence states"”.
-
The Challenge of Selectivity in Ethylene Oligomerization: Ligand Design and Metal Valence States
… chromium-aluminate complexes in different valence states. This allowed us to isolate a “single component” self activating Cr(II) complex as well as a rare example of mixed valence Cr(I)/Cr(II) species. Additionally, each of these species acted as switchable catalyst depending on the type of …
-
Multiphoton ionization of hydrogen iodide and molecular iodine using photoelectron spectroscopy
… dissociation due to the intermediate repulsive valence states is very strong for both HI and I$\sb2.$ For HI, the dissociative valence states correlate with H($\sp1$S) + I($\sp2$P$\sb{3/2,1/2});$ And for I$\sb2,$ they correlate with I($\sp2$P$\sb{3/2,1/2})$ + I($\sp2$P$\sb{3/2,1/2}).$ As a …
-
Chemical selection rules of single-phase high-entropy oxides
… (1) cation size mismatch, and (2) preferred valence states. The oxide candidates were synthesized by the polymeric steric entrapment method to ensure homogeneous mixing among the cations. The evolution of phase transformation and structural stability from room temperature up to ~2000C were …
-
The fixation of arsenic wastes
… complicated by the fact that it has a variety of valence states. This, coupled with the plurality of regulatory leaching test variants used, has made it impossible to gauge which of a number of Solidification/Stabilization (S/S) processes are the most effective. Cement based …
-
Bildung und Nutzung multinuklearer Titanocenkomplexe mit N-heterocyclischen Brückenliganden
… one electron oxidants. Thereby a number of mixed valence states have been shown to be accessible and were isolated as crystalline compounds. This allowed first investigations on the extent of electronic communication between titanium centers of different valency as well as the transfer of concepts …
-
A iron-57 Moessbauer study on the thermal oxidation of iron in biotite mica.
… spectroscopy, which resolves the 2+ and 3+ valence states of iron. The main features of the annealing time and temperature dependencies of the $\rm Fe\sp{3+}/Fe\sp{2+}$ amounts are understood in terms of a simple model in which: (i) the overall oxidation reaction proceeds homogeneously via a …
-
Electrical and structural properties of compositions in the systems Y₁₋ₓCaₓMnO₃ and La₁₋ₓCaₓMnO₃
… present in Mn perovskites only in the +3 and +4 valence states. A new defect model was developed which included the thermally excited disproportionation of Mn<sup>3+</sup> into Mn<sup>2+</sup> and Mn<sup>4+</sup> pairs. The Seebeck data could be explained with this model by assuming that divalent …
-
Vacuum-ultraviolet photoexcitation of some non-metal halides
… has resulted in the population of Rydberg states of the neutral molecule and outer valence states of the parent ion. The study has shown that the emitters in the range 190-690 nm are due to either, neutral fragments formed by dissociation of Rydberg states of the neutral molecule or excited …
-
Novel Transition-Metal Oxides Under Pressure
… mostly owe to our ability to adjust valence states and crystal fields, among others, by fine-tuning thermodynamic variables. From this tuning, interesting and sometimes competing properties emerge; but it is often necessary to take these oxides to extremes conditions of pressure, …
-
Mantle and crustal controls on the distribution of chalcophile elements in silicate melts
… benefits our understanding of how the relative valence states of Fe and S vary across different magmatic environments.
-
X-ray scattering studies of strongly correlated materials: orbital ordering in KCuF3 and stripe-like domain structures in BiFeO3 epitaxial thin films
… a spatial modulation of predominantly Fe 3d valence states with a period equal to that of the ferroelectric domain structure. The possibility of a magnetic origin to the Fe L3 edge resonant scattering is discussed. No O K edge resonant scattering was observed, indicating that O 2p states are …
-
Petroleum coke slags: characterization and dissolution
… to eliminate spurious data; (4) estimation of valence states of transition metals using thermodynamic and computational methods; (5) derivation of chemical formulae for the phases using computational methods and chemistry of ionic substitutions; (6) verification of phase identity using X-ray …
-
Density Functional Theory augmented Multiplet Ligand Field Theory Applied to X-ray Spectroscopy of 3d Transition Metals
… by the core-hole in the intermediate and final states. In this work, I surveyed 8 different 3d transition metal systems across the periodic table and analyze how calculated spectra reproduce trends across peak width, spin state, and integral intensity to conclusively demonstrate the accuracy of …
-
Structural and thermodynamic properties of sodium actinide ternary oxides
… not previously foreseen. The corresponding mixed valence state composition is written $Na_3(U_{1-x},Na_x)O_4$ with 0<$\textit{x}$<0.16(2). To complete the data on the Na-U-O system, the thermodynamic functions of $Na_2U_2O_7$ and $Na_4UO_5$ were evaluated using Knudsen effusion mass spectrometry …
-
Tuning Strong Correlated Properties in EuTiO3 Thin Films Grown by Pulsed Laser Deposition
… were made and found to be ferromagnetic. The valence states change of Ti ions were demonstrated using XPS, showing that 13.41% (x=0.3) and 34.59% (x=0.5) of extra electrons were bonded to Ti4+ effectively. FM in Eu1-xGdxTiO3 (x = 0.3, 0.5) thin films was explained by magnetic interactions …
-
Functional Oxides in Optical and Electronic Applications by Atmospheric Pressure Spatial Chemical Vapour Deposition
… (RRAM) due to their ability to alter resistance states, which is crucial for non-volatile memory applications. With the growing demand for efficient data storage, and processing driven by post-CMOS AI hardware, linked to Big Data and the Internet of Things, RRAM is being developed to achieve …
-
Redox properties of Bis-Triarylamines and ligand properties of Thianthrenophane
… of the corresponding X-B monomers. The excited states of the dimers are described as MV states which show, depending on the chemical nature of the bridge, a varying amount of interactions. It was found that superradiant emission only proceeds in the case of weak and medium coupling. Whether the …
-
Multipoles, Magnetic charges and chiral properties in antiferromagnetic materials inferred from resonant X-Ray diffraction
… by a few electrons around the atomic core in the valence states. The uses of x-rays and neutrons techniques, due to the huge development of large facilities as synchrotrons and spallation sources, have revealed many of these behaviours. In the case of synchrotron sources, photon beams have high …
-
Geochemical studies of earth materials
… slag. Vanadium is known to exist in multiple valence states in compounds which possess a wide range of melting points and physical properties. Consequently, it becomes important to carefully regulate oxygen fugacity throughout the system in order to control vanadium valence state. Wanadium …
-
Siderophile Element Partitioning at high Pressures and Temperatures : Implications for Core Formation Processes
… facilitates the identification of the valence states of these elements in the silicate phase. It was found that Cu and Ag are present as 1+ cations, Au and Pb are divalent, Sn and Ge have a valence of 3+ and Sb and As are tetravalent and pentavalent respectively. The addition of S to …