A theoretical investigation of the photo-induced intramolecular charge transfer excitation of cuprous (I) bis-phenanthroline by density functional theory

This work reported an investigation on the excited state and electronic transfer excitation of cuprous (I) bis-phenanthrouline complex by density functional theory. The intramolecular charge transfer from central metal to ligand (MLCT) during the excitation was observed. The transfer direction and degree were discussed on the basis of analyzing the Mulliken charge. The structural distortion caused by the charge transfer in the excited state was confirmed. The excited state was found having the characters similar with Cu(II) complex both in electronic and geometrical properties. The large structural distortion found between ground state and excited state could lead to a decrease in the lifetime of excited state as well as a non-radiative decay. The excitation energies and oscillator strengths of cuprous (I) bis-phenanthrouline were derived using time-dependent density functional method. The values of excitation energies are good agreement with the results of the experimental measuring.     

Temperature-dependent diffraction studies on the phase evolution of tetraindium heptabromide

The mixed-valent compound In₄Br₇ undergoes a higher-order phase transition below which leads to a decrease in symmetry from the trigonal to the monoclinic (C2/c) system via . The phase transition has been monitored by X-ray powder diffraction using a linear position-sensitive detector between 15 and , and the crystal structures at room temperature and at 90 K have been refined by means of time-of-flight neutron powder-diffraction data; at , the lattice parameters are , , , and β=98.20(1)°; the new unit cell contains 88 atoms (Z=8) of which 12 are symmetry-independent. Due to their electronic instability because of a second-order Jahn-Teller effect, two of the three crystallographically independent monovalent indium cations are severely affected by the phase transition with respect to their coordination spheres; bond-valence calculations reveal significant strengthening of In⁺-Br⁻ bonding upon symmetry reduction. Structural changes and group-subgroup relationships as well as possible intermediate phases are discussed.     

Pitting on the 20Kh13 steel in chloride solutions

The dependences of the pitting potential, determined by potentiodynamic method, on the NaCl solution concentration, pH, and temperature are found. The repassivation potential and the induction time for the pitting under different conditions are determined. The corrosion potential and kinetic parameters of the steel dissolution in pits are measured. The corrosion current is evaluated, leading to the determination of the steel dissolution rate in pits at the corrosion potential.     

Theoretical approach to the magnetic properties of Co(II) ion in CoL2·5H2O compound (L is 5-chloro-2-methoxybenzoate)

The magnetic moments of a Co(II) complex in a recently reported CoL₂·5H₂O compound (L is 5-chloro-2-methoxybenzoate, ClC₆H₃(OCH₃)COO^?) were studied by a semi-theoretical approach in the vicinity of tetragonal distortion. It was found that in order to obtain the observed temperature-dependent magnetic moments, some parameters in the magnetic Hamiltonian which are related to the geometry of the complex should be varied. Comparing the calculated results of this study with experimental results from the literature, a distorted octahedral environment of Co(II) ion in the compound is predicted. Also, rather high probability of large orbital contribution to the magnetic moment is expected. Some abnormalities in previously reported data might be reduced by taking the experimental data with VSM (Vibrational Susceptibility Magnetometer).     

Polysulfonylamine. LXXIII [1]. Metall(II)-dimesylamid-Tetrahydrate: Das Dimesylamid-Anion als einzähniger O-Ligand und tetrafunktioneller Wasserstoffbrücken-Akzeptor in den isotypen Komplexen [M(H2O)4 {(CH3SO2)2N}2] mit M = Magnesium,Nickel, Kupfer und Zink

Polysulfonyl Amines. LXXIII. Metal(II) Dimesylamide Tetrahydrates: The Dimesylamide Anion as a Monodentate O-Ligand and a Tetrafunctional Hydrogen Bond Acceptor in the Isotypic Complexes [M(H₂O)₄{(CH₃SO₂)₂N}₂], where M = Magnesium, Nickel, Copper, or Zinc By treating aqueous HN(SO₂CH₃)₂ solutions with the appropriate metal hydroxides, oxides, or carbonates, the crystalline tetrahydrates M[(CH₃SO₂)₂N]₂ · 4 H₂O (M = Mg, Ca, Mn, Co, Ni, Cu, Zn, Cd) were obtained and analytically characterized. The crystal structures of the Mg, Ni, Cu and Zn compounds, as determined by single-crystal X-ray diffraction at low temperatures, reveal an isotypic series (triclinic, space group P1 , Z = 1). The structures consist of centrosymmetric trans-octahedral [M(H₂O)₄{(CH₃SO₂)₂N}₂] molecules in which the anionic ligand acts as a monodentate O-donor. For the Mg, Ni and Zn complexes, the M? OH₂ and M? O(anion) distances lie in the ranges 203–206 pm and 209–214 pm, respectively. The copper compound features a marked Jahn-Teller distortion with Cu? OH₂ = 195.8 and 197.7 pm and Cu? O(anion) = 232.5 pm. The cis-angles O? M? O of the four molecules do not deviate appreciably from 90°. The complex units are associated through a highly organized three-dimensional hydrogen bond network in which all the water protons act as donors and the non-coordinating oxygen atoms and the nitrogen atom of the anionic ligand are involved as acceptors. The H-bond pattern is subjected to a graph-theoretical analysis at the first and second levels.     

铂修饰的稀土掺杂TiO2的光催化制氢活性

采用溶胶-凝胶浸渍法和光沉积法制备了系列Pt/RE/TiO₂纳米光催化剂, 通过XRD和电化学等手段进行了表征. 以甲醛为电子给体, 考察了光催化剂在紫外光照射下的制氢活性. 稀土掺杂提高了Pt/TiO₂光催化制氢活性, 其顺序分别为La/TiO₂＞Sm/TiO₂＞Eu/TiO₂＞Dy/TiO₂＞Er/TiO₂. 掺入稀土元素后, 阻止了TiO₂从锐钛矿晶型向金红石晶型的转变, 这是光催化剂活性提高的原因之一. 计算晶格畸变应力e数据表明, Ti^4＋可能反掺入了表面稀土氧化物的晶格中. 电化学实验表明稀土掺杂TiO₂的平带电位负移, 其原因可解释为晶格畸变促使费米能级升高, 导致催化剂导带的平带电位负移, 因此导带上被激发电子具有更强的还原能力, 从而有利于光催化制氢活性的提高.     

磁光盘原始误码特性测试中的等效性问题分析

在磁光盘原始误码特性测试过程中通常采用记“1”测漏码,或记“0”测冒码的方法测试盘片的误码性能。本文侧重分析了介质膜缺陷导致盘片产生误码的原因,建立了读出畸变信号与介质膜缺陷参量(如大小、位置、缺陷因子等)的数学模型。分析表明,在盘面记“1”和记“0”两种情况下,同一介质膜缺陷产生的信号畸变幅值相等,从而从理论上证明了记“1”测漏码与记“0”测冒码具有一定等效性。     

A note on asymptotically isometric copies of

Nonreflexive Banach spaces that are complemented in their bidual by an L-projection--like preduals of von Neumann algebras or the Hardy space --contain, roughly speaking, many copies of which are very close to isometric copies. Such -copies are known to fail the fixed point property. Similar dual results hold for .

     

Budget-constrained optimal insurance without the nonnegativity constraint on indemnities

In a problem of Pareto-efficient insurance contracting (bilateral risk sharing) with expected-utility preferences, Gollier (1987) relaxes the nonnegativity constraint on indemnities and argues that the existence of a deductible is only due to the variability in the cost of insurance, not the nonnegativity constraint itself. In this paper, we find support for a similar statement in problems of budget-constrained optimal insurance (i.e., demand for insurance). Specifically, we consider a setting of ambiguity (unilateral and bilateral) and a setting of belief heterogeneity. We drop the nonnegativity constraint and assume no cost (or a fixed cost) to the insurer, and we derive closed-form solutions to the problems that we formulate. In particular, we show that optimal indemnities no longer include a deductible provision; and they can be negative for small values of the loss, or in case of no loss.