Unusual mechanisms can dominate reactions at hyperthermal energies: an example from O(3P) + HCl --> ClO + H

An unusual mechanism in the reaction, O(3P) + HCl --> ClO + H, dominates at hyperthermal collision energies. This mechanism applies to collision geometries in which the H atom in the HCl molecule is oriented toward the reagent O atom. As the Cl-O bond forms, the H atom experiences a strong repulsive force from both the O and Cl atoms. The ClO product scatters forward with respect to the initial velocity of the O atom, and the H atom scatters backward. This mechanism accounts for more than half the reactive trajectories at energies >110 kcal mol-1, but it does not involve motion near the minimum energy path, which favors an SN2-like reaction mechanism where the H atom is oriented away from the reagent O atom during the collision.     

Plasmonic properties of film over nanowell surfaces fabricated by nanosphere lithography

In this work, a detailed and systematic study of the plasmonic properties of a novel film over nanowell surface is investigated. These nanostructures are fabricated using nanosphere lithography and reactive ion etching and structurally characterized by AFM and SEM. The resulting structures show remarkably narrow plasmon bands in reflectance spectra (as little as 0.10 eV) and greater sensitivity to external dielectric environment than has been seen in other nanoparticle systems, resulting in an improvement in the figure of merit (FOM = refractive index sensitivity (eV.RIU(-1))/full width at half-maximum (eV)) for refractive index sensing. Theoretical modeling for the plasmon spectra of these nanostructures is done using discrete dipole approximation code under periodic boundary conditions. The modeling results match the measurements accurately in aspects of the variation of the plasmon line shape with altering internanowell distance and dielectric environment.     

Electric quadrupole interaction of192Tl(8−) nuclei in hexagonal Tl and in tetragonal in metals

The TDPAD technique has been used to measure the electric quadrupole coupling constants for the¹⁹²Tl(8^–) isomer in hexagonal Tl at different temperatures and in tetragonal In at room temperature. The values measured weree ² qQ/h=24.0(15) MHz extrapolated toT=0K, and 33.1(16) MHz at 293K for the Tl and In hosts,respectively, The electric field gradient for Tl impurities in In was determined from systematics of isoelectric systems, yielding |Q[¹⁹²T1(8^–)]|=0.44(7)b.The almost perfect symmetry of the T1 crystalline structure makes this metal a sensitive probe to current models for electric field gradients in metals. The magnitude and temperature dependence of the field gradient in thallium metal are discussed within the framework of such models.     

Hydroxydfluoride von Kupfer und Cadmium

Zusammenfassung Aus fluoridhältigen Amminkomplexlösungen wurden durch Wegkochen des Ammoniaks die röntgenographisch scharf erfaßbaren Salze Cu(OH)F, Cu₇(OH)₁₀F₄, Cu₂(OH)₃F und Cd(OH)F isoliert. Diadochie der Ionen OH und F tritt nicht auf.Mit 1 Abbildung2. Mitt.:E. Hayek, P. Inama undB. Schatz, Mh. Chem.94, 366 (1963).     

Stroboscopic observation of quadrupole hyperfine interactions

A stroboscopic technique for the observation of quadrupole hyperfine interactions of isomeric nuclear states has been successfully developed. The inherent precision and resolution of this technique have been demonstrated by measuring the quadrupole hyperfine frequency for ${}^{69}\text{Ge(}\text{9}\text{2}{}^{\mathrm{+}}{}_1\text{, τ = 4.0μ)}$ in Zn metal at several temperatures; ω₀ = [19.67 ± 0.06] × 10⁶s^?1 (at 623 ± 3 K).     

Surface andinterface studies with perturbed angular correlations

The present status of surface, interface andthin film studies with perturbed -angular correlation (PAC) spectroscopy is reviewed. Applications include adsorbate diffusion andstructural phase transitions on stepped metal surfaces, surface andinterface magnetism as well as compound formation at reactive metal/metal interfaces. First applications to semiconductor surfaces andmetal/semiconductor interfaces are discussed.     

PAC investigations of Au(110) 1×2-surfaces

Au(110) surfaces with (1×2)-reconstruction have been investigated using perturbed -angular correlation (PAC) spectroscopy. From the two observed electric-field-gradient tensors at¹¹¹In probe atoms, deposited at room temperature in a concentration of about 10^–4 ML, the occupation of substitutional sites in the densely-packed rows along [110]-directions and ninefold coordinated sites within the (111)-oriented microfacets, respectively, can be concluded. Annealing to about 600 K leads to bulk migration of the In atoms, detected by an increase of probe atoms with cubic surroundings. Due to this behaviour the order-disorder transitions of these surfaces occurring atT _c=649 K cannot be detected in our PAC experiments.     

Über die Geometrie von Laguerre

Ohne Zusammenfassung