Topic
Valency
About: Valency is a research topic. Over the lifetime, 1632 publications have been published within this topic receiving 26141 citations.
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01 Jan 2008
TL;DR: In this article, the authors measured the Lη spectrum for a series of La1xSrxMnO3 from x=0 to 1 and investigated the correlation between the exchange-splitting energy and the Mn valency.
Abstract: Introduction Perovskite-type Mn oxides attract a great deal of interest from both fundamental and applicational viewpoints because of their interesting properties such as the CMR effect. The Mn 3d electrons in the compounds are closely related to those properties. The number of the 3d electrons in a given Mn compound can be evaluated by measuring the Mn 3s photoemission spectroscopy (PES) spectrum. The spectrum exhibits a double-peak structure, the so-called exchange splitting resulting from the exchange interaction between the Mn 3s hole and the Mn 3d electrons. The splitting energy depends on the number of the 3d electron or Mn valency. Galakhov et al. have illustrated the fair correlation between the splitting energy and the Mn valency of Mn oxide [1]. We also found the Mn 3s PES spectrum for Pr0.5Ca0.5MnO3 reflecting change in the Mn valency across the charge-order transition [2]. The PES spectrum is, however, more or less surfacesensitive and sometimes gives misleading information on the inherent bulk nature of the material. In addition the spectrum for the insulating material suffers the charging effect by photoirradiation. On the other hand x-ray emission spectroscopy (XES) is much less surfacesensitive and is not affected by the charging effect. The 3s-2p radiative transition leaves the 3s hole. Thus the Lη and Ll, i.e. 3s-2p1/2 and 3s-2p3/2, respectively, XES spectra for Mn compounds also exhibit the exchange splitting. It has been found that the Lη spectrum for Mn oxides does exhibit the double-peak structure reminiscent of the Mn 3s PES spectrum, whereas it is hard to evaluate undoubtedly the splitting energy in the Ll spectrum [3]. We have measured the Lη spectrum for a series of La1xSrxMnO3 from x=0 to 1 and investigate the correlation between the exchange-splitting energy and the Mn valency of La1-xSrxMnO3.
TL;DR: In this article, the X-ray photoelectron spectra of α-Sb2O4 and BaBiO3 were analyzed and the mixed-valency character of these oxides was found only after careful pretreatment of the samples in situ.
Abstract: X-Ray photoelectron spectra of the metal(III)–metal(V) oxides α-Sb2O4 and BaBiO3 are reported. Indications of ‘mixed-valency’ character in the metal core-electron spectra could be found only after careful pretreatment of the samples in situ. Under normal conditions both compounds appear to have surface phases containing just the lower oxidation state.
01 Jun 2016
TL;DR: Several types of discontinuities are identified, which are classified either by the verb class or structurally in terms of the verb, its arguments and their dependents, which is especially important for languages with a relatively free word order, such as Czech.
Abstract: We describe results of investigation of a specific type of discontinuous constructions, namely non-projective constructions concerning verbs and their arguments. This topic is especially important for languages with a relatively free word order, such as Czech, which is the language we have primarily worked with. For comparison, we have included some results for English. The corpora used for both languages are the Prague Czech-English Dependency Treebank and the Prague Dependency Treebank, which are both annotated at a dependency syntax level as well as a deep (semantic) level, including verbs and their valency (arguments). We are using traditionally defined non-projectivity on trees with full linear ordering, but the two levels of annotation are innovatively combined to determine if a particular (deep) verb -argument structure is non-projective. As a result, we have identified several types of discontinuities, which we classify either by the verb class or structurally in terms of the verb, its arguments and their dependents. In addition, we have quantitatively compared selected phenomena found in Czech translated texts (in the PCEDT) to the native Czech as found in the original Prague Dependency Treebank.
TL;DR: In this paper, the morphology and morphophonology of the basic conjugational categories of the Mbalanhu verb are described, i.e., mood, simple tense, and aspect.
Abstract: In this article the morphology and morphophonology of the basic conjugational categories of the Mbalanhu verb are described. These categories are mood (those inflectionally marked properties of the verb that relate clauses to possible worlds), simple tense (as opposed to compound tense; simple tense is regarded as those inflectional properties of the verb that indicate deixis between coding time and event time), and aspect (those agglutinating properties of the Mbalanhu verb that signal the internal temporal structure of the event described by the verb).
TL;DR: In this paper, the dependence of the electron mobility on the iron impurity content NFe and temperature is studied for three variants of the ordering of Fe3+ ions in crystalline HgSe:Fe, a weakly correlated gas.
Abstract: The dependence of the electron mobility on the iron impurity content NFe and temperature is studied for three variants of the ordering of Fe3+ ions in crystalline HgSe:Fe, a weakly correlated gas, states with near ordering like that in a strongly correlated Coulomb liquid, and long-range ordering. The electron mobilities owing to scattering on the correlated system of Fe3+ ions are determined. The temperature dependence of the mobility is analyzed for electron scattering on fluctuations in the charge density in a system of Fe2+-Fe3+ iron ions with mixed valency, and the correlation length is determined. It is shown that the ordering region for the Fe3+ ions encompasses only the first coordination sphere, i.e., near ordering in the position of the Fe3+ ions is established, as in a liquid. The coupling between the ordering of the Fe3+ ions and the formation of a correlation gap in the density of impurity d-states and its effect on the low-temperature behavior of the electron mobility in HgSe:Fe crystals are examined.