A method for the numerical inversion of Laplace transforms

In this paper a numerical inversion method for Laplace transforms, based on a Fourier series expansion developed by Durbin [5], is presented. The disadvantage of the inversion methods of that type, the encountered dependence of discretization and truncation error on the free parameters, is removed by the simultaneous application of a procedure for the reduction of the discretization error, a method for accelerating the convergence of the Fourier series and a procedure that computes approximately the ‘best’ choice of the free parameters. Suitable for a given problem, the inversion method allows the adequate application of these procedures. Therefore, in a big range of applications a high accuracy can be achieved with only a few function evaluations of the Laplace transform. The inversion method is implemented as a FORTRAN subroutine.     

Efficient algorithms to enumerate isomers and diamutamers with more than one type of substituent

In this paper we describe numeric as well as symbolic algorithms for the enumeration of substitutional isomers with an unlimited number of different achiral substituents. We consider three different scenarios: first, the enumeration of diamutamers with a given set of ligand types and ligand multiplicity, second, the enumeration of diamutamer libraries with a given ligand assortment pattern, and, third, the enumerations of libraries with diamutamers exhibiting a limited number of ligands.     

Nonlinear electric field effects at a continuous mott-hubbard transition

We characterize the non-Ohmic portion of the conductivity at temperatures T<1 K in the highly correlated transition metal chalcogenide Ni(S,Se)(2). Pressure tuning of the T = 0 metal-insulator transition reveals the influence of the quantum critical point and permits a direct determination of the dynamical critical exponent z = 2.7(+0.3)(-0.4). Within the framework of finite temperature scaling, we find that the spatial correlation length exponent nu and the conductivity exponent &mgr; differ.     

Interplay between orbital and magnetic long range order by resonant X-ray scattering in (V1−xCrx)2O3

Resonant X-ray scattering experiments have been performed in 2.8% Cr-doped V₂O₃ single crystal at the Vanadium K-photoabsorption edge. Using linear polarization analysis and comparing the angular dependence of scattered photons with structure factor calculations we can discriminate the nature of the different resonant X-ray processes involved in forbidden lattice reflections enhanced by resonances. We present an experimental method to extract information on local properties of edge-atom such as the anisotropy of the local atomic environment, the atomic magnetic moment orientation and orbital ordering.     

Ziegler–Natta polymerization of butadiene: Kinetic and molecular weight study

The effect of reaction conditions on conversion and molecular weight in the polymerization of butadiene initiated by cobalt octoate/diethylaluminum chloride/water was studied. The polymerization exhibited complex kinetics with respect to cobalt concentration. The molecular weight, as a function of conversion, was investigated. Chain transfer to aluminum alkyl was of only minor importance.