Double-β decay of116Cd

The NEMO-2 tracking detector located in the Fréjus Underground Laboratory was designed as a prototype of the detector NEMO-3 to study 0ν and 2ν double-beta decay (ββ) physics. After ten months of nearly continuous running with an enriched cadmium source (0.92 mol·y of¹¹⁶Cd) aββ2ν half-life ofT _1/2=(3.75±0.35(stat)±0.21(syst))·10¹⁹ y was measured. Limits with 90% CL on the¹¹⁶Cd half-lives of 5.0·10²¹ y forββ0ν decay and of 1.2·10²¹ y forββ0νχ ⁰ decay with a Majoron (χ ⁰) were obtained. Theoretical predictions for 0ν and 2ν decays of¹¹⁶Cd are also presented.     

One-nucleon stripping reactions to discrete levels induced by a 793 MeV16O beam on a208Pb target

One-proton and one-neutron stripping reactions induced by a 793 MeV¹⁶O beam bombarding a²⁰⁸Pb target have been studied at the GANIL facility using a high resolution energy loss magnetic spectrometer. The reactions are governed by two semi classical selection rules which are naturally contained in the one-step EFR-DWBA formalism. Relative intensities of the populated states are well reproduced by this formalism which, on the other hand, fails to predict correctly absolute cross section values.     

Synthesis and structural study of novel 1,4,5,6,7,8‐hexahydroquinolines

A new series of 1,4,5,6,7,8‐hexahydroquinolines (9a‐j) has been synthesized and their structural features studied by X‐ray analysis and theoretical calculations at semiempirical and ab initio levels. A good correlation is found between the most stable conformation predicted for compounds 9 and that obtained by experimental X‐ray diffraction for 9h. The obtained geometrical features for 9 are similar to those found for other related active calcium modulators.     

A full conformational space analysis of bilirubin

Ab initio methods were utilized in a gas-phase systematic conformational search of bilirubin conformers. The whole molecule was divided into four fragments. Most stable conformers of them were employed to build 196 conformers of the complete bilirubin molecule. Initial geometries were optimized using HF/3-21G level of theory and the minimum energy conformers were then reoptimized at B3LYP/6-31G(d) level. Ridge-tile conformer was the most stable one, in perfect agreement with X-ray data. We found that while tetrapyrrole backbone shows some flexibility, propionic acid side chains have a greater influence in bilirubin conformation because they can interact through different hydrogen bond patterns with the backbone and between them.     

ZnO nanoparticles embedded in UVM-7-like mesoporous silica materials: Synthesis and characterization

ZnO nanodomains embedded in bimodal mesoporous silica (UVM-7) materials with high Zn content (4≤Si/Zn≤30) have been synthesized by an one-pot surfactant-assisted procedure from a hydro alcoholic medium using a cationic surfactant (CTMABr=cetyltrimethylammonium bromide) as structural directing agent, and starting from molecular atrane complexes of Zn and Si as hydrolytic inorganic precursors. This chemical procedure allows optimizing the dispersion of the ZnO particles in the silica walls. The bimodal mesoporous nature of the final high surface area nano-sized materials is confirmed by XRD, TEM, and N₂ adsorption–desorption isotherms. The small intra-particle mesopore system is due to the supramolecular templating effect of the surfactant, while the large pores have their origin in the packing voids generated by aggregation of the primary nanometric mesoporous particles. A limited pore blocking and a high accessibility to the ZnO active nanoparticles have been achieved. The effects induced by the progressive incorporation of ZnO nanoparticles into the mesostructure have been examined, including a careful optical spectroscopic study (PL and UV–visible).     

Study of 2β-decay of 100Mo and 82Se using the NEMO3 detector

After analysis of 5797 h of data from the detector NEMO3, new limits on neutrinoless double beta decay of ¹⁰⁰Mo (T _1/2>3.1×10²³y, 90% CL) and ⁸²Se (_{T 1/2}>1.4×10²³y, 90% CL) have been obtained. The corresponding limits on the effective majorana neutrino mass are: 〈m _v〉<(0.8–1.2) eV and 〈m _v〉<(1.5–3.1) eV, respectively. Also the limits on double-beta decay with Majoron emission are: T _1/2>1.4×10²²y (90% CL) for ¹⁰⁰Mo and T _1/2>1.2×10²²y (90% CL) for ⁸²Se. Corresponding bounds on the Majoron-neutrino coupling constant are 〈 g _ee〉<(0.5–0.9)×10^?4 and <(0.7?1.6)×10^?4. Two-neutrino 2β-decay half-lives have been measured with a high accuracy, $T_{1/2}^{100_{Mo} } = [7.68 \pm 0.02(stat) \pm 0.54(syst)] \times 10^{18} y$ and $T_{1/2}^{82_{Se} } = [10.3 \pm 0.3(stat) \pm 0.7(syst)] \times 10^{19} y$ .     

Coherent control of optical emission from a conjugated polymer

We have observed that resonant Rayleigh scattering dominates the emission from poly(p-phenylene vinylene) excited with photons at energies below the threshold at which excitonic migration is reduced. The intensity of the resonant emission decays exponentially with a lifetime of up to 450 fs after pulsed excitation. The coherent nature of the emission was confirmed by angular variations in the far-field emission intensity-bright and dark speckles. Persistence of a coherent polarization was demonstrated by coherent control using phase-locked pulses.     

Synthesis, crystal structure, and molecular modeling (AM1) of Methyl 6-chloro-4-(2-chlorophenyl)-5-formyl-2-methyl-1, 4-dihydropyridine-3-carboxylate

The synthesis and structural characterization of Methyl 6-chloro-4-(2-chlorophenyl)-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate is described. The structure was refined to R₁ = 0.0470 for 2665 reflections (with I > 2(I)). Crystal data: C₁₅H₁₃C₁₂NO₃, monoclinic,space group P2₁/c, a = 11.163(9), b = 14.484(8), c = 9.422(7) Å, V = 1512.9(19) ų, Z = 4. The results of crystallographic and molecular modeling (AM1) were compared. The Cl atom attached to the phenyl group has two possible orientations, having 75% (sp) and 25% (ap) occupancy, respectively. The molecules in the crystal are held together by means of intermolecular hydrogen bonds of the type N=H...O and by C=H...O interactions.     

Physico-chemical study of the ternary system: isotactic polybutene-1-cyclohexane-n-propyl alcohol. Influence of molecular weight on the preferential adsorption phenomenon

This paper presents results on the influence of molecular weight on the preferential adsorption coefficient. λ, for the ternary system: isotactic polybutene-1-cyclohexane-n-propyl alcohol. It has been found that there are two different theta points.