نتایج جستجو برای: valence / charge
تعداد نتایج: 157948 فیلتر نتایج به سال:
Tolazoline is a non-selective competitive α-adrenergic receptor antagonist. It is a vasodilator that is used to treat spasms of peripheral blood vessels (as in acrocyanosis).Tolazoline is indicated in the treatment of persistent pulmonary hypertension in the newborn (persistent fetal circulation) when systemic arterial oxygenation cannot be maintained by supplemental oxygen and mechanical venti...
Published two-body bond-valence parameters for cation-oxygen bonds have been evaluated via the root mean-square deviation (RMSD) from the valence-sum rule for 128 cations, using 180,194 filtered bond lengths from 31,489 coordination polyhedra. Values of the RMSD range from 0.033-2.451 v.u. (1.1-40.9% per unit of charge) with a weighted mean of 0.174 v.u. (7.34% per unit of charge). The set of b...
We present the refinement of the crystal structure of charge-ordered LuFe2O4, based on single-crystal x-ray diffraction data. The arrangement of the different Fe-valence states, determined with bond-valence-sum analysis, corresponds to a stacking of charged Fe bilayers, in contrast with the polar bilayers previously suggested. This arrangement is supported by an analysis of x-ray magnetic circu...
In this research work at The first compounds [C60- 2-(naftalin-1-ilmetil)-4,5-dihidro-1H-imidazol-C65-2X]+ (X=F,Cl,Br) were optimized. Then the calculation of natural bond orbitals was performed with the NBO technique. All calculations using Hartree- fock the 6-31G * basis set using Gaussian 98 software and in gas phase has been done. The results showed that the energy levels of mol...
Valence-skip compound is a good candidate with high T c and low anisotropy because it has a large attractive interaction at the site of valence-skip atom. However, it is not easy to synthesize such compound because of (i) the instability of the skipping valence state, (ii) the competing charge order, and (iii) that formal valence may not be true in some compounds. In the present study, we show ...
Weshow that repulsive local Coulomb interaction alone can drive valence-skipping charge disproportionation in the degenerate d-band, resulting in effective negative-U . This effect is shown to originate from anisotropic orbitalmultipole scattering, and it occurs only for d1, d4, d6, and d9 fillings (and their immediate surroundings). Explicit boundaries for valence-skipping are derived, and the...
We explore the relationship between grand canonical (GC) ensemble and charge equilibration (CE), also known as electronegativity equalization, theories for describing charge flow in molecules. We introduce a new unifying approach to classical charge transfer theories based on valence bond (VB) theory and the maximum entropy (ME) method, which we call MEVB. We show how MEVB reduces to GC and CE ...
Charge densities of iso-structural metal hexaborides, a transparent metal LaB6 and a semiconductor BaB6, have been determined using the d > 0.22 Å ultra-high resolution synchrotron radiation X-ray diffraction data by a multipole refinement and a maximum entropy method (MEM). The quality of the experimental charge densities was evaluated by comparison with theoretical charge densities. The stron...
Transmission electron diffraction (TED) combined with direct methods have been used to study the sqrt[3]xsqrt[3]R30 degrees reconstruction on the polar (111) surface of MgO and refine the valence charge distribution. The surface is nonstoichiometric and is terminated by a single magnesium atom. A charge-compensating electron hole is localized in the next oxygen layer and there is a nominal char...
Tunneling spectroscopy has been used to detect the photoexcitation of charge carriers in the wide band-gap semiconductors, ZnO and cubic SiC. Because the process is energy sensitive, valence-toconduction hand or defect charge transfer transitions may be selectively excited and detected with the scanning tunneling microscope. Two types of transitions were detected which change the tunneling resp...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید