Correlation and solvation effects. IV. A systematic analysis of the influence of cavity size and shape on solvation properties in the polarizable continuum model with electron correlation

From the standpoint of models that use a polarizable continuum to represent the solvent in studying the phenomenon of solvation, a systematic and detailed analysis is made of the influence of the cavity size and shape on calculated energies. The solute is represented by its ab initio wavefunction, and the electronic part of the solvation energy is calculated including terms that take into account electron correlation up to third order. The analysis shows the convenience of modeling the cavity according to considerations of homogeneity, which are based fundamentally on how the solute wavefunction is constructed, i.e., the basis set used.     

The crystal structure of triphenylallyltin

The crystal structure of (C₆H₅)₃SnCH₂CHCH₂ has been determined. The asymmetric unit consists of two molecules of triphenylallyltin having virtually the same conformation. Their geometrical parameters exclude p_π-d_π bonding between the metal and the allyl double bond, and seem to be in a better agreement with a σ-π conjugation effect.     

The crystal and molecular structure of bis(thiourea)iron (11) thiocyanate

Summary The crystal structure of bis(thiourea)iron(II) thiocyanate, Fe[SC(NH₂)₂]₂(NCS)₂, has been determined and refined by three-dimensional x-ray analysis. The complex crystallizes in the triclinic system, space group P –1, witha = 10.114(6),b = 7.662(8),c = 3.897(10) Å, = 105.0(2)°, = 81.8(3)°, = 96.4(3)° andz = 1. It is isostructural with M(tu)₂(NCS)₂, where M = Mn, Co or Ni and to = thiourea. The iron atom is located on a centre of symmetry and is coordinated to four planar sulfur atoms of the thiourea ligands (Fe-S 2.61 and 2.65 Å) and two nitrogen atoms of the thiocyanate groups (Fe-N 2.05 Å) in a distorted octahedral way. These octahedra are linked in chains with each thionilic sulfur atom shared by two adjacent iron atoms; magnetic measurements, Mössbauer and spectroscopic data are consistent with this polymeric structure.     

Demodulation of Spatial Carrier Images: Performance Analysis of Several Algorithms Using a Single Image

Optical full-field techniques have a great importance in modern experimental mechanics. Even if they are reasonably spread among the university laboratories, their diffusion in industrial companies remains very narrow for several reasons, especially a lack of metrological performance assessment. A full-field measurement can be characterized by its resolution, bias, measuring range, and by a specific quantity, the spatial resolution. The present paper proposes an original procedure to estimate in one single step the resolution, bias and spatial resolution for a given operator (decoding algorithms such as image correlation, low-pass filters, derivation tools …). This procedure is based on the construction of a particular multi-frequential field, and a Bode diagram representation of the results. This analysis is applied to various phase demodulating algorithms suited to estimate in-plane displacements.     

Synthesis of new materials based on polythiophenes substituted with mesogen groups

A new family of conjugated polymers formed by 3-alkyloximethylthiophenes substituted with a biphenyl group was synthesised by a route involving first the coupling of a functionalised alkyl chain, from 8 to 12 carbon atoms, to 3-methanolthiophene, and then the attachment of the mesogen group. The monomer was characterised by conventional techniques, and thermal studies were also achieved. The polymerisation of these units was carried out via oxidative polymerisation with FeCl₃. The resultant polymers were characterised by FT-IR, elemental microanalysis and XPS. Subsequently, these materials were doped with I₂ and characterised by the above techniques and conductivity measurements, which indicated that these materials are in the semiconductor range. The polymerisation of these monomers was also carried out via electrochemical methods, and it was found that, together with the oxidation of the thiophene ring, the oxidation of the biphenyl group is also produced, for which an over-oxidised material is obtained, as demonstrated by XPS analysis and theoretical calculations.     

Time-Resolved Digital Image Correlation in the Scanning Electron Microscope for Analysis of Time-Dependent Mechanisms

Experimental Mechanics - Background: Advancements in the Digitial Image Correlation (DIC) technique over the past decade have greatly improved spatial resolution. However, many processes, such as...