Search results for "absorption."

Spin state, electronic structure and bonding on C-scorpionate [Fe(II)Cl2(tpm)] catalyst: An experimental and computational study

2020

Abstract The Fe(II) spin state in the condensed phase of [Fe(II)Cl2(tpm)] (tpm = [tris(pyrazol-1-yl)methane]; 1) catalyst has been determined through a combined experimental and theoretical investigation of X-Ray Absorption Spectroscopy (XAS) at the FeL2,3-edges and NK-edge. Results indicated that in this phase a mixed singlet/triplet state is plausible. These results have been compared with the already know Fe singlet spin state of the same complex in water solution. A detailed analysis of the electronic structure and bonding mechanism of the catalyst showed that the preference for the low-spin diamagnetic ground state, strongly depends upon the ligands, the bulk solvent and the interactio…

Accumulation of radiation defects and modification of micromechanical properties under MgO crystal irradiation with swift 132Xe ions

2020

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. A.A. also acknowledges support via the project GF AP05134257 of Ministry of Education and Science of the Republic of Kazakhstan .

Local structure of ball-milled LaNi5 hydrogen storage material by Ni K-edge EXAFS

2010

Abstract Local structure of the nanostructured LaNi5 hydrogen storage alloys, prepared by ball-milling, has been studied using Ni K-edge extended X-ray absorption fine structure spectroscopy. Results indicate that the ball-milling up to 100 h results in the production of nanoparticles characterized by large atomic disorder and slightly reduced unit-cell volume, compared to the bulk LaNi5. High temperature annealing appears to help in partial recovery of atomic order in the ball-milled samples; however, long-time ball-milled samples retain large disorder even after the high temperature annealing. The results suggest that the large disorder and the reduced unit-cell volume might be causing a …

Modeling the interactions between light and crystallizing polymer during fast cooling

2004

In this work, an experimental set-up able to quench thin polymer films whilst recording the sample thermal history as well as the overall and depolarized light intensities of a laser beam emerging from the sample is described. The interactions between the light beam and the crystallizing material have been modeled accounting for absorption and scattering phenomena. The proposed model was found to be able to reproduce the ex- perimentally observed behavior of light intensities and it was validated by comparison with conventional DSC analysis. On the basis of this model, a method to obtain crystallinity evo- lution is proposed and applied to some fast cooling runs. The method was applied to q…

7 YEARS OF EUROPEAN FUNDING IN ROMANIA - BETWEEN SUCCESS AND FAILURE

2015

This paper aims to achieve an overall picture of the absorption rate of European funds in Romania for the 2007-2013 programming period and to propose a series of recommendations on the steps our country needs to follow in order to improve the process of accessing and implementation of structural instruments at national level. These recommendations focus on preventing obtaining a low rate of absorption of EU funds allocated to Romania in the multiannual financial framework 2014-2020 , thus preventing wastage prospects of economic and social modernization , that these funds offer.

Phototransition of Na(3p3/2) into high Rydberg states and the ionization continuum

2005

A model potential method is used to investigate photoabsorption from the Na(3p3/2) state. Absorption cross sections into higher Rydberg states and photoionization cross sections are presented as an analytical function of photo electron energy. Einstein coefficients for spontaneous emissions 3p3/2 ← ns1/2, nd5/2, nd3/2 are tabulated for n up to 50. The Einstein coefficients and low-energy ionization cross sections are believed to be accurate to better than 2–3%, above 1 eV the error may increase to 4–6%.

X-ray absorption spectroscopic study of trivalent and tetravalent actinides in solution at varying pH values

2009

Abstract We perform X-ray absorption spectroscopy (XAS) investigations to monitor the stabilization of redox sensitive trivalent and tetravalent actinide ions in solution at acidic conditions in a pH range from 0 to 3 after treatment with holding reductants, hydroxylamine hydrochloride (NH2OHHCl) and Rongalite (sodium hydroxymethanesulfinate, CH3NaO3S). X-ray absorption near edge structure (XANES) measurements clearly demonstrate the stability of the actinide species for several hours under the given experimental conditions. Hence, structural parameters can be accurately derived by extended X-ray absorption fine structure (EXAFS) investigations. The coordination structure of oxygen atoms be…

En-Face differential absorption optical coherence tomography with gold nanorods as the contrast agent

2008

A new variety of nanoparticles showing unique and characteristic optical properties, appeals for its use as contrast agents in medical imaging. Gold nanospheres, nanorods and nanoshells with a silica core are new forms of promising contrast agents which can be tuned to specific absorption or scattering characteristics within the near-infrared (NIR) spectrum ranging from 650 - 1300 nm. They have the ability to be used for both image enhancement and as photosensitive markers due to their well designable scattering and absorption properties. Furthermore, their strong optical absorption permits treatment of malignant cells by photoablation processes, induced when heating them with a matched lig…

Picosecond absorption spectroscopy: Methods and applications in photophysical and photochemical systems

1985

Special needs and characteristic features of (photo)catalytic reactors with a review of the proposed Solutions

2019

Abstract In the present chapter, the analogies between photocatalytic systems and the systems where the more common thermally activated reactions take place are highlighted. The objective is to propose a unified approach for the analysis and the design, which, however, must take into account how and why photocatalytic reactors differ from reactors with thermal reactions. The necessity of absorbing photons to activate the photocatalytic process adds complexity to the system, but some approaches are presented to simplify the problems and make easier their solution.