Didier Gourier

French National Centre for Scientific Research | CNRS

Collecter des informations chimiques sur les matériaux employés par Léonard de Vinci permet de mieux comprendre la matérialité de ses pratiques picturales et fournit de nouvelles informations pouvant contribuer à la conservation de ses œuvres. Mais les peintures de Léonard sont des systèmes chimiques complexes, assemblages hybrides de pigments miné...

This manuscript reports on the effect of ultraviolet (UV) and sunlight irradiated fingernail samples by electron paramagnetic resonance (EPR) in Q-band. Two UV-induced signals were identified and studied in detail. The first one labeled as UVIS2, was measured shortly after UVA radiation. The parameters of the UVIS2 are very similar to those from th...

Des matériaux de couleurs noires que nous appelons « matières noires » ont souvent été employés en contexte funéraire dans l’Égypte ancienne. Elles sont présentes, au sein des collections muséales, notamment sur des momies, des figurines, des vases canopes et des éléments de cercueils. Ces matières qui résultent d’un mélange complexe et chimiquemen...

A novel analysis of cathodoluminescence (CL) and ion-beam induced luminescence (IBIL) is presented on the basis of virtual photon spectra (VPS) produced by charged particles (electrons or ions) passing by luminescent species such as defects or impurities, in wide band-gap ionic-covalent solids. A discussion is provided for irradiations in a wide ra...

Photoluminescence (PL) undermonochromatic illumination in theUV-Vis-NIR (200–1000 nm), and Reflectance Imaging Spectroscopy (RIS) in the visible and near-infrared domain (NIR, 700–1000 nm) are well-established techniques which usefully complements X-ray fluorescence spectrometry (XRF) in the study of paintworks. PL under UV illumination allows the...

Photoluminescence (PL) under monochromatic illumination in the UV-Vis-NIR (200–1000 nm), and Reflectance Imaging Spectroscopy (RIS) in the visible and near-infrared domain (NIR, 700–1000 nm) are well-established techniques which usefully complements X-ray fluorescence spectrometry (XRF) in the study of paintworks. PL under UV illumination allows th...

Most inorganic pigments, as earths and ochres, have no luminescence emission. Sporadically, the literature has reported the presence of a weak optical emission for some of these pigments. However, this should be attributed to the presence of material impurities within pigments. In addition to this, a small number of inorganic pigments exhibit a cle...

Is it possible to reconstruct the gesture of an ancient artist applying a paint layer, considering that the orientation distribution of crystallites of an inorganic pigment remains definitively imprinted on the support after drying of the layer? If the pigment contains paramagnetic transition metal ions whose magnetic interactions are themselves an...

Is it possible to reconstruct the gesture of an ancient artist applying a paint layer, considering that the orientation distribution of crystallites of an inorganic pigment remains definitively imprinted on the support after drying of the layer? If the pigment contains paramagnetic transition metal ions whose magnetic interactions are themselves an...

Ancient Egyptian mummies from the Late Period to the Greco–Roman Period were covered by a black coating consisting of complex and heterogeneous mixtures of conifer resins, wax, fat and oil with variable amounts of bitumen. Natural bitumen always contains traces of vanadyl porphyrin complexes that we used here as internal probes to explore the nanos...

Ancient Egyptian mummies from the Late Period to the Greco-Roman period were covered by a black coating consisting in a complex and heterogeneous mixtures of conifer resins, wax, fat and oil with variable amounts of bitumen. Natural bitumen always contains traces of vanadyl porphyrin complexes that we used here as internal probes to explore the nan...

How the transport of fluids in a confined and complex mixed organic/inorganic matrix can be far below the expected value from topological aspect? A good example of this situation is oil shales. Oil and gas shales are source rocks in which organic matter has matured to form hydrocarbons. They exhibit a dual porous network formed by the intertwining...

Human nails have been studied for many years for potential use for dosimetry, based on the EPR signals induced by ionizing radiation, but a fully validated protocol to measure doses retrospectively has not yet been developed. The major problem is that the EPR spectrum of irradiated nails is complex and its radiation-induced signals (RIS) overlap wi...

Advanced EPR techniques such as ENDOR and pulsed EPR are used to investigate the enigmatic black coatings of ancient Egyptian mummies, consisting in a complex and heterogeneous mixtures of conifer resins, wax, fat and oil with variable amounts of bitumen. Natural bitumen always contains traces of vanadyl porphyrin complexes that we used here as int...

Advanced EPR techniques such as ENDOR and pulsed EPR are used to investigate the enigmatic black coatings of ancient Egyptian mummies, consisting in a complex and heterogeneous mixtures of conifer resins, wax, fat and oil with variable amounts of bitumen. Natural bitumen always contains traces of vanadyl porphyrin complexes that we used here as int...

The damage recovery of an electron-irradiated CeO2 single crystal was studied by in situ UV-visible absorption spectroscopy during isochronal thermal annealing up to 873 K. The spectrum of the as-irradiated crystal shows band tailing below the fundamental absorption edge for photon energy near 3.2 eV. Two broad Gaussian bands centered at about 0.9...

Monitoring the formation of dendrites or filaments of lithium is of paramount importance for Li-based battery technologies, hence the intense activities in designing in situ techniques to visualize their growth. Herein we report the benefit of correlating in situ electron paramagnetic resonance (EPR) spectroscopy and EPR imaging to analyze the morp...

Leonardo da Vinci (1452–1519) is a key artistic and scientific figure of the Renaissance. He is renowned for his science of art, taking advantage of his acute observations of nature to achieve striking pictorial results. This study describes the analysis of an exceptional sample from one of Leonardo’s final masterpieces: The Virgin and Child with S...

The black matter employed in the funeral context by ancient Egyptians is a complex mixture of plant-based compounds with variable amounts of bitumen. Asphaltene, the most resistant component of bitumen, contains vanadyl porphyrins and carbonaceous radicals, which can be used as paramagnetic probes to investigate embalming materials without sample p...

The black matter employed in funeral context by ancient Egyptian is a complex mixture of plant-based compounds with variable amounts of bitumen. Asphaltene, the most resistant component of bitumen, contain Vanadyl porphyrins and carbonaceous radicals which can be used as paramagnetic probes to investigate embalming materials without sample preparat...

div>Monitoring the formation of dendrites or filaments of lithium is of paramount importance for Li-based battery technologies, hence the intense activities in designing in situ techniques to visualize their growth. Herein we report the benefit of correlating in situ electron para4 magnetic resonance (EPR) spectroscopy and EPR imaging to analyze...

ABSTRACT In-situ cathodoluminescence (CL) spectroscopy is used to study point-defect formation in cerium dioxide (CeO2) by high-energy electrons (400 keV-1250 keV) at ~100 K, 200 K, and 300 K in a high-voltage electron microscope (HVEM). Complementary CL spectra are also obtained for 20-keV electron excitation at ~300 K in a scanning electron micro...

The oldest carbonaceous matter in the solar system, aged at 4.5 billion years old, can be found trapped in meteorites. On Earth, the oldest carbonaceous matter of biological origin is fossilised in cherts dated at 3.5 billion years old. The EPR study of samples of this primitive carbonaceous matter provides information on the nature, the environmen...

Reflection spectra of cerium dioxide sintered samples were measured in the UV-visible range after irradiation with various heavy ions (2.4-MeV Cu, 5-MeV W, 10-MeV W, 36-MeV W, 100-MeV Kr, and 200-MeV Xe). Differential reflectance spectra of irradiated samples after subtraction of the reference sample spectrum are fit with six broad Gaussian bands c...

Rédigé dans la foulée de l’Année européenne du patrimoine culturel, ce numéro spécial de la revue Reflets de la Physique et du Bulletin de l’Union des professeurs de physique et de chimie présente des aspects complémentaires de la physique moderne des matériaux de l’archéologie, de l’histoire de l’art, de l’histoire naturelle et des sciences de la...

Copper acetate and copper resinate pigments are bimetallic Cu II complexes in which metal atoms are bridged by four carboxylate ligands (acetate or abietate). Prepared with lindseed oil as binder, these green pigments were particularly used in easel paintings between the 15th and 17th centuries. Unfortunately, they had the tendency to darken in an...

Zinc oxide (ZnO), used as a pigment since the 19th C., is highly reactive when mixed with drying oils. Indeed, the combination of metal-based pigments and drying oils may react to form metal complexes in paint, which may lead to the aggregation of metal carboxylates or soaps. Whereas the mechanism and chemistry behind metal soap formation has been...

SM related to "Monitoring metal ion leaching in oil-ZnO paint systems with a paramagnetic probe"

Electron paramagnetic resonance (EPR) analysis of carbonaceous, volcanic, tidal sediments from the 3.33 Ga-old Josefsdal Chert (Kromberg Formation, Barberton Greenstone Belt), documents the presence of two types of insoluble organic matter (IOM): (1) IOM similar to that previously found in Archean cherts from numerous other sedimentary rocks in the...

Traditional “stack “manufacturing process (16–19th c.) of lead white pigment by lead corrosion is explored by exposing metal to acetic acid, carbon dioxide, dioxygen and water vapor. Global reaction scheme is revealed, along with stratification of corrosion products with CO2 gradient, leading to flakiness of corrosion layer. Kinetic and epitaxial f...

Highly transparent glass ceramics, synthesized from a glass precursor with a nominal composition of SiO2/ZnO/Ga2O3/Na2O/Cr2O3 (65:17:23:5:0.125), were prepared by glass crystallization. This method enables the synthesis of up to 50 wt.-% of size-controllable Cr3+ -doped ZnGa2O4 nanocrystals embedded in an SiO2-rich glass matrix after crystallizatio...

Analytical techniques using proton beams with energy in the MeV range are commonly used to study archeological artefact and artistic objects. However ion beams can induce alteration of fragile materials, which is notably the case of easel paintings, limiting the use of these techniques. We used continuous wave EPR and pulse EPR spectroscopy to reve...

The lead white pigment, composed of two main mineral phases cerussite PbCO3 and hydrocerussite 2PbCO3.Pb(OH)2, has been used in paintings since the Antiquity. The study of historical sources revealed that a large variety of lead white qualities were proposed, depending on the degree of sophistication of the pigment synthesis. Investigation of photo...

We have studied in this work the effect of increasing structural disorder on the persistent luminescence of a Cr(3+) doped zinc gallate spinel. This disorder was introduced by progressive substitution of Zn(2+) by Mg(2+) ions, and was studied by photoluminescence, X-ray diffraction, extended X-ray absorption fine structure (EXAFS), X-ray absorption...

Le développement de l’instrument et des méthodes d’analyse par faisceau d’ions appliquées aux problématiques patrimoniales est au cœur de l’activité de l’équipe AGLAE. Le projet New AGLAE a pour objectif de mettre à disposition des chercheurs une ligne de faisceau automatisée et en fonctionnement jour et nuit, ainsi qu’un nouveau système de détecti...

Cr 3+ -doped zinc gallate ZnGa 2 O 4 is a red-near infrared (IR) long persistent phosphor that can be excited by orange-red light, in the transparency window of living tissues. With this property, persistent luminescence nanoparticles were recently used for in vivo optical imaging of tumors in mice. In order to understand the origin of the excitabi...

Abstract The analysis of the optical spectroscopy of the Cr3+ doped spinel was initiated by Prof. Georges Boulon more than twenty years ago. More recently persistent luminescence nanoparticles of Cr doped zinc gallate have found interest for in vivo imaging of small animals. Here we evaluated near infra-red (NIR) excitation (or NIR photostimulation...

Cr³⁺-activated Y3Al2Ga3O12 garnet (YAGG:Cr³⁺) persistent phosphor has been recently reported as a potential candidate material for in vivo imaging application. Temperature dependence of photoluminescence (PL) spectra and thermostimulated luminescence (TSL) glow curves with several conditions, especially photostimulation wavelength dependence, were...

In the prospect of manufacturing ionizing radiation detectors, dense ceramics of α-HgI2 with a strong preferred orientation were elaborated. X-ray diffraction showed that most crystallites exhibited their crystal c-axis perpendicular to the ceramic plane, which should be favorable for optimum electrical transport properties. Dark current densities...

Abstract Persistent luminescence is a singular property of some materials which are able to store the excitation or light irradiation energy at intrinsic traps or defects before slowly emitting lower energy photons within several hours. When such compounds are prepared as nanoparticles (NPs), when functionalization is realized to get colloidal mate...

X-ray absorption near edge structure (XANES) spectroscopy technique is used to better understand the charging and decharging processes of the persistent luminescence in the Cr3+ doped AB2O4 spinels (A = Zn, Mg and B = Ga and Al) with low photon energy excitation by visible light. Cr K edge XANES spectra have been simulated for different near neighb...

We presently introduce a novel generation of optical nanoprobes, based on chromium-doped zinc gallate, whose persistent luminescence can be activated in vivo through living tissues using highly penetrating low energy photons from the red region of the visible spectrum. Surface functionalization of this photonic nanoprobe can be adjusted to favor mu...

Batteries for electrical storage are central to any future alternative energy paradigm. The ability to probe the redox mechanisms occurring at electrodes during their operation is essential to improve battery performances. Here we present the first report on Electron Paramagnetic Resonance operando spectroscopy and in situ imaging of a Li-ion batte...

In the last decade human nails have been investigated as a possible biological indicator of exposure to ionizing radiation. Radiation-induced radicals detected by Electron Paramagnetic Resonance (EPR) spectroscopy can be used to quantify the received dose. However, possible additional EPR signals due to nail polish have not been yet investigated. A...

Cr3+ doped spinel compounds AB2O4 with A=Zn, Mg and B=Ga, Al exhibit a long near infrared persistent luminescence when excited with UV or X-rays. In addition, persistent luminescence of ZnGa2O4 and to a lesser extent MgGa2O4, can also be induced by visible light excitation via 4A2 [rightward arrow] 4 T2 transition of Cr3+, which makes these compoun...

ZnGa2O4 (ZGO) is a normal spinel. When doped with Cr³⁺ ions, ZGO:Cr becomes a high brightness persistent luminescence material with an emission spectrum perfectly matching the transparency window of living tissues. It allows in vivo mouse imaging with a better signal to background ratio than classical quantum dots. The most interesting characterist...

Insoluble organic matter (IOM) conserved in ancient sedimentary rocks and in carbonaceous meteorites can reveal valuable information about the origin of Life on Earth and on the birth of the Solar System, respectively. These IOMs are also reference materials for the search for possible organic traces of extinct life on Mars. The combination of cont...

Optical imaging for biological applications requires more sensitive tools. Near-infrared persistent luminescence nanoparticles enable highly sensitive in vivo optical detection and complete avoidance of tissue autofluorescence. However, the actual generation of persistent luminescence nanoparticles necessitates ex vivo activation before systemic ad...

Investigations are currently performed on matrices for the specific immobilization of long-lived radionuclides such as fission products resulting from an enhanced reprocessing of spent fuel. Hollandite (nominally BaAl2Ti6O16), one of the phases constituting Synroc, receives renewed interest as specific Cs-host wasteform. The radioactive cesium isot...

ZnGa2O4 (ZGO) is a normal spinel. When doped with Cr3+ ions, ZGO:Cr becomes a high brightness persistent luminescence material with an emission spectrum perfectly matching the transparency window of living tissues. It allows in vivo mouse imaging with a better signal to background ratio than classical fluorescent NIR probes. The most interesting ch...

Red emitting long-lasting phosphorescence (LLP) material, are useful biomarker for small animal in vivo imaging. We report here our investigations on the optical features of chromium doped AB2O4 spinels (A=Zn, Mg and B=Ga, Al…) suitable for such applications. It is possible to tune the emission wavelengths of Cr3+ by a crystal field variation to be...

Verdigris is a green copper organometallic pigment, widely used in paintings during the fifteenth and sixteenth centuries. With ageing, chromatic modifications like browning or darkening can be observed on those green painted layers. An original but crucial approach has been developed based on the characterization of a reference neutral verdigris p...

Until very recently, analysis of bone biopsies by means of the method of electron paramagnetic resonance (EPR) collected after surgery or amputation has been considered as the sole reliable method for radiation dose assessment in hands and feet. EPR measurements in finger- and toenail have been considered for accident dosimetry for a long time. Hum...

ZnGa2O4:Cr3+ presents near-infrared long-lasting phosphorescence (LLP) suitable for in vivo bio-imaging. It is a bright LLP material showing a main thermally-stimulated luminescence (TSL) peak around 318K. The TSL peak can be excited virtually by all visible wavelengths from 1.8 eV (680 nm) via d-d excitation of Cr3+ to above ZnGa2O4 band gap (4.5...

Abstract The search for organic biosignatures is motivated by the hope of understanding the conditions of emergence of life on Earth and the perspective of finding traces of extinct life in martian sediments. Paramagnetic radicals, which exist naturally in amorphous carbonaceous matter fossilized in Precambrian cherts, were used as local structural...

This study aims at determining biogenicity and syngenicity markers for Archean cherts. To this end, we studied the kerogens from nine cherts of various ages (Devonian to Archean), localities and metamorphic facies through a combination of microscopic, spectroscopic and pyrolytic methods. All samples were shown to be in the carbonization stage witho...

A new red-emitting long-lasting phosphorescence (LLP) material useful as biomarker for small animal in vivo imaging is presented. X-ray irradiated MgGa2O4 : Cr3+ is shown to be a suitable persistent phosphor emitting in the range 650–770 nm. In vivo re-excitation of its persistent luminescence is also possible with 580 nm excitation. MgGa2O4 : Cr3+...

We have recently introduced the use of persistent luminescence nanoparticles, or long-lasting phosphors, for in vivo bioimaging applications in living animals. Red long-lasting phosphors possess an emission located in the tissue transparency window, between 600 and 900 nm, allowing their use for in vivo imaging. Thanks to their optical properties,...

Electron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. The classical EPR parameters are the peak-to-peak amplitude, the linewidth and the $g$ factor; however, such parameters turn out not to suffice to full...

The mechanism of decoherence of the electron spin of Ti(3+) in β-Ga2O3 was investigated by pulsed electron paramagnetic resonance. At 4.2 K, both instantaneous and spectral diffusion contribute to the decoherence. For electron spin concentrations ≈10(25) m(-3) in the studied samples, calculations indicate that electron-electron couplings and electr...

Last generation medical imaging equipments require materials which possess outstanding performances. For scintillators in the high energy imaging field (PET), crystals with high light yields allow a decrease of the irradiation dose received by the patients during medical application and a more accurate diagnostic. Thermally stimulated luminescence...

Ce:LYSO (Lu 1.90 Y 0.1 SiO 5 :Ce) single crystals were prepared by the Czochralski technique. We report some effects of the X-ray irradiation on the shape of the emission spectra. For instance a large decrease of the longest wavelength emission (at about 500 nm) is observed with an increase of the light yield after one hour under X-ray irradiation....

Ancient geological materials are likely to be contaminated through geological times. Thus, establishing the syngeneity of the organic matter embedded in a mineral matrix is a crucial step in the study of very ancient rocks. This is particularly the case for Archean siliceous sedimentary rocks (cherts), which record the earliest traces of life. We u...

Organic radicals in artificially carbonized biomass dominated by oxygenic and non-oxygenic photosynthetic bacteria, Microcoleus chthonoplastes-like and Chloroflexus-like bacteria respectively, were studied by Electron Paramagnetic Resonance (EPR) spectroscopy. The two bacteria species were sampled in mats from a hypersaline lake. They underwent acc...

CaMgSi2O6:Mn diopsides are used for in vivo long-lasting phosphorescence (LLP) imaging. Trapping defects involved in the LLP mechanism were investigated. On annealing Mn-doped diopsides at 1100 °C in an Ar–H2 atmosphere, Ca EXAFS/XANES and electron paramagnetic resonance (EPR) evidenced paramagnetic oxygen vacancies while X-ray diffraction, Mn XANE...

Barium hollandite-type ceramics have been envisaged for the immobilization of radioactive cesium. To evaluate their stability under irradiation, a hollandite ceramic of composition Ba1.16Al2.32Ti5.68O16 was irradiated with electrons at a temperature close to room temperature to simulate the effect of β- and γ-decays of cesium. Ti3+ and O2- paramagn...

The datation of photosynthesis apparition remains an open question nowadays: did oxygenic photosynthesis appear just before the Great Oxidation Event (GOE) of the atmosphere, 2.3 to 2.4 Gyr ago, or does it originate much earlier? It is therefore of uttermost interest to find markers of oxygenic photosynthesis, applicable to samples of archean age....

Electron Paramagnetic Resonance (EPR) spectroscopy and imaging are based on the interaction of a microwave electromagnetic field (typically in the GHz range) with electron spins in presence of an external magnetic field. Contrary to UV-visible and Infrared light, microwave radiation can penetrate in most non conducting materials, so that EPR is sen...

Ca2Si5N8:Eu²⁺,Tm³⁺ presents outstanding long lasting luminescence at about 610 nm. However, to be useful for in vivo optical imaging, persistent luminescence materials should possess high optical performance combined with sizes in the nanoscale. With this aim, we investigated two different techniques for the preparation of nanoparticles from Ca2Si5...

Regarding its ability to circumvent the autofluorescence signal, persistent luminescence was recently shown to be a powerful tool for in vivo imaging and diagnosis applications in living animal. The concept was introduced with lanthanide-doped persistent luminescence nanoparticles (PLNP), from a lanthanide-doped silicate host Ca0.2Zn0.9Mg0.9Si2O6:E...

The nature, properties and relative concentrations of electronic defects were investigated by Thermoluminescence (TL) in Lu2(1-x)Y2xSiO5 (LYSO) single crystals. Ce and Tb-doped single crystals, grown by the Czochralski technique (CZ), revealed similar traps in TL. LYSO: Ce single crystals were grown by the Floating-Zone technique (FZ) with increasi...

Focusing on the use of nanophosphors for in vivo imaging and diagnosis applications, we used thermally stimulated luminescence (TSL) measurements to study the influence of trivalent lanthanide Ln(3+) (Ln = Dy, Pr, Ce, Nd) electron traps on the optical properties of Mn(2+)-doped diopside-based persistent luminescence nanoparticles. This work reveals...

We studied the nuclear-nuclear spin interaction mediated by an unpaired electron spin, focusing on an isotopic effect by electron nuclear double resonance (ENDOR) spectroscopy. We investigated a linear cluster Ga-Ti3+-Ga in titanium-doped gallium oxyde β-Ga2O3, whereby the unpaired electron spin density of Ti3+ is equally delocalized on the nuclear...

ZnGa2O4:Cr3+ is shown to be a new bright red UV excited long-lasting phosphor potentially suitable for in vivo imaging due to its 650 nm-750 nm emission range. Photoluminescence and X-ray excited radioluminescence show the 2E → 4A2 emission lines of both ideal Cr3+ and Cr3+ distorted by a neighboring antisite defect while long-lasting phosphorescen...

Using electron paramagnetic resonance (EPR) under band-gap illumination, we show experimental evidence of a defect center in n-type cubic silicon carbide (3C-SiC) single crystal irradiated with 1-MeV electrons. This defect is diamagnetic (S=0) in its ground state and can be pumped into a paramagnetic (S=1, MS=0) state by above-band-gap photon excit...

The insoluble organic matter (IOM) of the Orgueil meteorite contains deuterium-rich radicals detectable by Electron Paramagnetic Resonance (EPR) techniques (Gourier et al., 2008). However the structure of these deuterium carriers remains poorly constrained. In this work, their electronic structure is deduced from the measurement of the spin states...

The hyperfine interactions of the unpaired electron with eight surrounding 69Ga and 71Ga nuclei in Ti-doped β-Ga2O3 were analyzed by electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopies. They are dominated by strong isotropic hyperfine couplings due to a direct Fermi contact interaction with Ga nuclei i...

Red persistent luminescent diopside nanoparticles doped with Mn2+ and codoped with RE3+ (Eu2+, Dy3+) have been obtained by sol-gel method. The influence of codoping rare earth ions on the persistent luminescence was studied by wavelength-resolved thermally stimulated luminescence (TSL) measurements from 30 to 650K after X-ray irradiation. From thes...