Bound -> free and bound -> bound multichannel emission spectra from selectively excited Rydberg states in the ZnAr and CdAr van der Waals complexes

Multichannel dispersed emission spectra recorded upon a selective excitation of Rydberg electronic energy states in the ZnAr and CdAr van der Waals (vdW) complexes are analysed as a proof-of-concept of the future experimental approach. Simulations of the emission spectra are based on ab-initio calculated interatomic potentials and transition dipole moments (TDMs). Experimental set-up that is under construction along with the experimental procedure are discussed

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

Using fullerène as catalyst support for proton exchange membrane fuel-cells

Ce travail concerne l'étude de nouveaux catalyseurs à base de fullerène pour la cathode de piles à combustible de type PEMFC. L'utilisation du fullerène C60, réputé stable, comme support de catalyseur ainsi que la possibilité de lier le platine sur le fullerène permet d'espérer améliorer la tenue à la dégradation de la couche active. Dans un premier temps, un ensemble de catalyseur de type MnC60 à base d'atomes de platine et/ou palladium liés au C60, appelés métallofullerènes, ont été synthétisés et caractérisés physico-chimiquement. En parallèle, des catalyseurs non-nobles à base de phtalocyanine de fer déposée sur du fullerène ont également été synthétisés. Les performances de ces catalyseurs ont été testées électrochimiquement, sur une électrode tournante à disque-anneau, en demi-cellule et, pour les meilleurs catalyseurs, en pile, et comparées à celles obtenues avec des catalyseurs commerciaux de référence sur noir de carbone Pt/C et PtCo/C. Il ressort de l'étude que les performances des métallofullerènes dépendent de la stœchiométrie n des composés MnC60 et que les meilleurs présentent des performances similaires voire supérieures à celles obtenues avec les catalyseurs de référence. Les catalyseurs non-nobles sur fullerène permettent d'obtenir des performances similaires à celles obtenues avec des catalyseurs non-nobles sur noir de carbone. De plus, une première étude de vieillissement des métallofullerènes montrent que ces composés ont une résistance à la corrosion du carbone similaire aux catalyseurs de référence.This work concerns the study of new fullerene-based catalysts for the cathode of fuel cell type PEMFC. The use of fullerene C60, known to be stable, as a catalyst support and the ability to bind the platinum on the fullerene can hope to improve the resistance to degradation of the active layer. As a first step, a set of type catalyst MnC60 based on platinum and / or palladium atoms bonded to C60, called metallofullerenes, were synthesized and characterized physically and chemically. In parallel, non-noble catalysts based on iron phthalocyanine deposited on fullerene have been synthesized. The performance of these catalysts were electrochemically tested on a rotating ring-disk electrode, half-cell and, for best catalysts in fuel-cell, and compared with those obtained with reference commercial catalysts on carbon black Pt/C and PtCo/C. It appears from the study that the performance of metallofullerenes depends on the stoichiometry n of MnC60 compounds and best of them exhibit performance similar or even superior to those obtained with the reference catalysts. Non-noble catalysts on fullerene can obtain performance similar to those obtained with non-noble catalysts on carbon black. In addition, an initial study of metallofullerenes aging shows these compounds have a carbon corrosion resistance similar to reference catalysts

Using fullerène as catalyst support for proton exchange membrane fuel-cells

Ce travail concerne l'étude de nouveaux catalyseurs à base de fullerène pour la cathode de piles à combustible de type PEMFC. L'utilisation du fullerène C60, réputé stable, comme support de catalyseur ainsi que la possibilité de lier le platine sur le fulThis work concerns the study of new fullerene-based catalysts for the cathode of fuel cell type PEMFC. The use of fullerene C60, known to be stable, as a catalyst support and the ability to bind the platinum on the fullerene can hope to improve the resis

Utilisation de fullerène comme support de catalyseur pour les piles à combustible de type PEMFC

Ce travail concerne l étude de nouveaux catalyseurs à base de fullerène pour la cathode de piles à combustible de type PEMFC. L utilisation du fullerène C60, réputé stable, comme support de catalyseur ainsi que la possibilité de lier le platine sur le fullerène permet d espérer améliorer la tenue à la dégradation de la couche active. Dans un premier temps, un ensemble de catalyseur de type MnC60 à base d atomes de platine et/ou palladium liés au C60, appelés métallofullerènes, ont été synthétisés et caractérisés physico-chimiquement. En parallèle, des catalyseurs non-nobles à base de phtalocyanine de fer déposée sur du fullerène ont également été synthétisés. Les performances de ces catalyseurs ont été testées électrochimiquement, sur une électrode tournante à disque-anneau, en demi-cellule et, pour les meilleurs catalyseurs, en pile, et comparées à celles obtenues avec des catalyseurs commerciaux de référence sur noir de carbone Pt/C et PtCo/C. Il ressort de l étude que les performances des métallofullerènes dépendent de la stœchiométrie n des composés MnC60 et que les meilleurs présentent des performances similaires voire supérieures à celles obtenues avec les catalyseurs de référence. Les catalyseurs non-nobles sur fullerène permettent d obtenir des performances similaires à celles obtenues avec des catalyseurs non-nobles sur noir de carbone. De plus, une première étude de vieillissement des métallofullerènes montrent que ces composés ont une résistance à la corrosion du carbone similaire aux catalyseurs de référence.This work concerns the study of new fullerene-based catalysts for the cathode of fuel cell type PEMFC. The use of fullerene C60, known to be stable, as a catalyst support and the ability to bind the platinum on the fullerene can hope to improve the resistance to degradation of the active layer. As a first step, a set of type catalyst MnC60 based on platinum and / or palladium atoms bonded to C60, called metallofullerenes, were synthesized and characterized physically and chemically. In parallel, non-noble catalysts based on iron phthalocyanine deposited on fullerene have been synthesized. The performance of these catalysts were electrochemically tested on a rotating ring-disk electrode, half-cell and, for best catalysts in fuel-cell, and compared with those obtained with reference commercial catalysts on carbon black Pt/C and PtCo/C. It appears from the study that the performance of metallofullerenes depends on the stoichiometry n of MnC60 compounds and best of them exhibit performance similar or even superior to those obtained with the reference catalysts. Non-noble catalysts on fullerene can obtain performance similar to those obtained with non-noble catalysts on carbon black. In addition, an initial study of metallofullerenes aging shows these compounds have a carbon corrosion resistance similar to reference catalysts.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Rheology of cellulose nanofibrils/silver nanowires suspension for the production of transparent and conductive electrodes by screen printing

International audienceWith the aim of processing silver nanowires-based electrodes using screen printing process, this study proposes to evaluate the suitability of cellulose nanofibrils (CNF) as a thickening agent for providing a high viscosity silver nanowires screen printing ink. Rheology of CNF suspension has been specifically investigated according to screen printing process requirements using both rotational and oscillating rheology. It has been found that CNF indeed act as a thickener and stabilizer for the silver nanowires suspension. However, the solid dominant visco-elastic behavior of the CNF suspension was not suitable for screen printing and leads to defects within the printed film. CNF visco-elastic properties were modified by adding hydroxypropylmethyl cellulose (HPMC) to the suspension. Homogeneous transparent conductive layers have been obtained when using CNF-HPMC as a matrix for silver nanowires. The screen printed layers were characterized and performances of Rsh = 12 ± 5 Ω□−1 and T%500nm = 74,8% were achieved without any additional post-treatment to the film

Inkjet printing of nanocellulose–silver ink onto nanocellulose coated cardboard

International audienceCellulose nanocrystals (CNC) have recently been used in the field of flexible electronics. The present work proposes to evaluate the contribution of CNC in the inkjet printing of silver conductive tracks. The potential of CNC to enhance both ink and substrate properties for printed electronics application was evaluated. First, CNC potential to be used as a scaffold for silver nanoparticles production in a compatible silver inkjet ink was evaluated. It has been found that the CNC dispersing properties, combined to their nanometrical rod-shape, allowed producing conductive suspensions at very low silver content comparing to classical silver ink. Inkjet printing of the CNC–silver suspension was then investigated on several substrates. Among these substrates, CNC coated cardboard has been studied to propose a new alternative for the printing of conductive tracks onto a porous substrate like cardboard. It appears that the CNC coating significantly limits the ink diffusion into the porous substrate by modification of the ink drop absorption kinetics, leading to the printing of well-defined conductive patterns. By using CNC in both ink formulation and substrate pre-treatment, the produced conductive patterns are nearly only composed of cellulosic material, offering new prospects in the development sustainable electronics

Absorption spectrum of Ca atoms attached to 4He nanodroplets

Within density functional theory, we have obtained the structure of 4 He droplets doped with neutral calcium atoms. These results have been used, in conjunction with newly determined ab initio 1 and 1 Ca-He pair potentials, to address the 4s4p 1 P1←4s2 1 S0 transition of the attached Ca atom, finding a fairly good agreement with absorption experimental data. We have studied the drop structure as a function of the position of the Ca atom with respect to the center of mass of the helium moiety. The interplay between the density oscillations arising from the helium intrinsic structure and the density oscillations produced by the impurity in its neighborhood plays a role in the determination of the equilibrium state, and hence in the solvation properties of alkaline earth atoms. In a case of study, the thermal motion of the impurity within the drop surface region has been analyzed in a semiquantitative way. We have found that, although the atomic shift shows a sizable dependence on the impurity location, the thermal effect is statistically small, contributing by about 10% to the line broadening. The structure of vortices attached to the calcium atom has been also addressed, and its effect on the calcium absorption spectrum discussed. At variance with previous theoretical predictions, we conclude that spectroscopic experiments on Ca atoms attached to 4 He drops will be likely unable to detect the presence of quantized vortices in helium nanodrops

Berichte - Dokumentation - Chronik

Renato Kizito Sesana - Die Missionspresse ItaliensRainald Merkert - Die Wandlung des Neil PostmanThomas A. Krosnicki - Liturgie als kommunikatives Geschehen]ürgen Hoeren -Der Papstbesuch und die MedienMichael Kessler - Massenkommunikation und Medienarbeit als SeminarthemaHelmut Rakowski - Literaturbericht zum Thema "Gottesdienstübertragungen im Fernsehen"Franz-]osef Eifers - Kulturen, Medien und christliche Wert