Search results for " Magne"

Erratum to ‘Raman spectroscopy of β-irradiated silica glass’ by B. Boizot, S. Agnello, B. Reynard, R. Boscaino and G. Petite [J. Non-Cryst. Solids 32…

2004

Variable fractional Fourier processor: a simple implementation: erratum

1997

Phonons in MoSe2/WSe2 van der Waals heterobilayer

2021

We report first-principles calculations of the structural and vibrational properties of the synthesized two-dimensional van der Waals heterostructures formed by single-layers dichalcogenides MoSe2 and WSe2. We show that, when combining these systems in a periodic two-dimensional heterostructures, the intrinsic phonon characteristics of the free-standing constituents are to a large extent preserved but, furthermore, exhibit shear and breathing phonon modes that are not present in the individual building blocks. These peculiar modes depend strongly on the weak vdW forces and has a great contibution to the thermal properties of the layered materials. Besides these features, the departure of fl…

Synchrotron x-ray transmission measurements and modeling of filters investigated for Athena

2020

International audience; Advanced Telescope for High-Energy Astrophysics is a large-class astrophysics space mission selected by the European Space Agency to study the theme "Hot and Energetic Universe." The mission essentially consists of a large effective area x-ray telescope and two detectors: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). Both instruments require filters to shield from out-of-band radiation while providing high transparency to x-rays. The mission is presently in phase B; thus, to consolidate the preliminary design, investigated filter materials need to be properly characterized by experimental test campaigns. We report results from high-resolution…

Towards Controlled Synthesis of Water-Soluble Gold Nanoclusters : Synthesis and Analysis

2019

Water-soluble gold nanoclusters with well-defined molecular structures and stability possess particular biophysical properties making them excellent candidates for biological applications as well as for fundamental spectroscopic studies. The currently existing synthetic protocols for atomically monodisperse thiolate-protected gold nanoclusters (AuMPCs) have been widely expanded with organothiolates, yet the direct synthesis reports for water-soluble AuMPCs are still deficient. Here, we demonstrate a wet-chemistry pH-controlled synthesis of two large water-soluble nanoclusters utilizing p-mercaptobenzoic acid (pMBA), affording different sizes of plasmonic AuMPCs on the preparative scale (∼7 …

An Easy Route Towards Regioselectively Difunctionalized Cyclens and New Cryptands.

2006

Reductive amination of various aldehydes with cyclen represents a very convenient method for the synthesis of a wide range of 1,7-difunctionalized cyclens, as well as new cryptands.

Isophorone on Au/MgO/Ag(001) : Physisorption with Electrostatic Site Selection

2017

We report a computational study of isophorone C9H14O adsorption on a Ag(001)-supported ultrathin MgO film with Au adatoms and clusters employing density functional theory calculations. The calculations show that the keto form of isophorone is more stable than the enol tautomers both in gas phase and on the MgO/Ag(001) surface. The interaction between the keto isophorone and step and terrace sites of MgO/Ag(001) displays long interaction distances, relatively weakly exothermic adsorption energies, lack of charge transfer, and minor changes in the density of states, all of which indicate that the molecule merely physisorbs on the surface. The step sites are energetically preferred adsorption …

Theoretical Analysis of the M12Ag32(SR)404– and X@M12Ag32(SR)304– Nanoclusters (M = Au, Ag; X = H, Mn)

2014

We analyze the electronic structure and optical properties of the recently reported, structurally known M12Ag32(SR)304– clusters (M = Au, Ag) by using density functional theory and time-dependent density functional perturbation theory. Effects of the chemical changes in the metal core, charge of the cluster, and nature of the thiolate ligand on the electronic structure and optical absorption are reported. In addition, doping the metal core with a magnetic transition metal atom (Mn) or hydrogen (protons) is discussed. Although all these clusters can be considered as 18-electron superatoms with a shell configuration 1S2 1P6 1D10, we find that the optical spectrum is sensitive to the charge st…

Ultrafast electronic relaxation and vibrational cooling dynamics of Au 144(SC2H4Ph)60 nanocluster probed by transient mid-IR spectroscopy

2014

Energy relaxation dynamics of a gold nanocluster with atomically precise composition, Au144(SC2H4Ph)60, is studied by transient mid-IR spectroscopy. The experiment is designed to simultaneously pro...

TDDFT Analysis of Optical Properties of Thiol Monolayer-Protected Gold and Intermetallic Silver–Gold Au144(SR)60 and Au84Ag60(SR)60 Clusters

2014

The optical absorption spectra of atomistic model structures for experimentally isolated all-gold Au144(SR)60 and intermetallic Au84Ag60(SR)60 clusters are systematically analyzed from linear-response time-dependent density functional theory (LR-TDDFT) and time-dependent density functional perturbation theory (TD-DFPT) calculations. The computed spectra, utilizing the atomistic model for Au144(SR)60 published by us in 2009, reproduce closely the experimental observations for corresponding isolated compounds, reported previously by Kumara and Dass in 2011. A collective dipole oscillation within the metal cores of the all-gold and intermetallic clusters is formed as response to light in the v…