Isotope and temperature effects in liquid water probed by x-ray absorption and resonant x-ray emission spectroscopy

High-resolution x-ray absorption and emission spectra of liquid water exhibit a strong isotope effect. Further, the emission spectra show a splitting of the 1b1 emission line, a weak temperature effect, and a pronounced excitation-energy dependence. They can be described as a superposition of two independent contributions. By comparing with gas phase, ice, and NaOH/NaOD, we propose that the two components are governed by the initial state hydrogen bonding configuration and ultrafast dissociation on the time scale of the O 1s core hole decay.     

Conductivity in an activity gradient

A procedure to evaluate conductivity measurements on a sample exposed to an activity gradient is presented The method allows the measured mean conductivity to be subsequently associated with a denned activity It offers not only an experimentally simple alternative to the Wagner-Hebb experiment, but also enables detailed information to be obtained about the activity dependence of the conductivity in polarization measurements with two blocking electrodes as well as in concentration cell experiments, no matter whether a two- or four-point arrangement is used It is further shown how the steady-state activities, which are necessary to compute the desired mean value, can be obtained from the initial and boundary conditions     

The radiation of rotating magnetic dipoles in vacuo in general relativity

An approximate solution of Maxwell's equations for the rotating oblique magnetic dipole is given on the geometrical background of the Schwarzschild metric. The energy radiation is calculated for both the case of the Schwarzschild geometry and the linearized Kerr metric on the basis of the Newman-Penrose formalism. It is shown that general relativistic effects are not sufficient to explain by themselves the experimentally measured slowdown laws of realistic pulsars.     

Efficient stimulated Raman scattering in silicon

Stimulated Raman scattering in silicon was investigated at liquid helium temperatures. A Q-switched single mode Nd: YAG laser was used to generate Stokes radiation at 1.127 μm. Time resolved measurements give a maximum power conversion efficiency of 20%. The effects of intensity induced losses are discussed.     

The impact parameter dependence of the Pb + Pb K − MO spectrum

Molecular orbital X-rays are emitted during ion-atom collisions. The theoretical treatment, numerical results for the Pb + Pb system and a comparison with background radiation like NNB, SEB and γ-decay of Coulomb excited nuclei are presented.     

Calculation of wavefunctions and frequencies for noninfinitesimal vibrations: Comparison of various methods using ab initio CI potential curves

Three computational methods employing different means of representing molecular potentials are used to obtain wavefunctions and energy levels for noninfinitesimal vibrations. An interpolation scheme based on a cubic spline fitting procedure is introduced to supplement the CI energy results obtained explicitly in actual calculations. As long as a representative set of potential points is available it is found that the results of all three methods (two of variational and one of numerical integration type) are quite consistent, for both bending and stretching vibrations of ground and electronically excited states (examples for HCN and O₂ are considered). In addition a comparison of one- and two-dimensional bending vibrational treatments is made.     

Phase transitions in experimental systems

Scaling functions of the support and of the measure have been used to characterize the scaling behavior of a dynamical system. While scaling functions for the scaling of the measure, ƒ(), have been calculated for a number of experimental systems, examples of scaling functions φ(λ) for the scaling of the support are difficult to obtain. In this contribution, we report on a phase-transition-like effect of an experimental p-doped germanium semiconductor sample. It is found that the results obtained from the dynamical scaling function agree with those obtained by Horita et al. from model maps, indicating that scaling functions for the scaling of the support are a powerful method of characterizing experimental dynamical systems.     

A note to the paper “An efficient algorithm for linear programming” of V Ch Venkaiah

In Venkaiah [1] an algorithm for solving linear optimization problems based on the idea of the projective algorithm of Karmarkar, is proposed. The essential simplification in the new algorithm is the use of a fixed projection operator. In this way the algorithm requires onlyO(n ² ) operations to obtain a sufficient exact solution. In this note it is shown that in some special cases the algorithm of Venkaiah yields a feasible solution that is far from the optimal one.