Abstract: Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of λ/δλ ~ 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 μm. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm2 g−1 account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

Abstract: Band gap narrowing is important and advantageous for potential visible light photocatalytic applications involving metal oxide nanostructures. This paper reports a simple biogenic approach for the promotion of oxygen vacancies in pure zinc oxide (p-ZnO) nanostructures using an electrochemically active biofilm (EAB), which is different from traditional techniques for narrowing the band gap of nanomaterials. The novel protocol improved the visible photocatalytic activity of modified ZnO (m-ZnO) nanostructures through the promotion of oxygen vacancies, which resulted in band gap narrowing of the ZnO nanostructure (Eg = 3.05 eV) without dopants. X-ray diffraction, UV-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, Raman spectroscopy, photoluminescence spectroscopy and high resolution transmission electron microscopy confirmed the oxygen vacancy and band gap narrowing of m-ZnO. m-ZnO enhanced the visible light catalytic activity for the degradation of different classes of dyes and 4-nitrophenol compared to p-ZnO, which confirmed the band gap narrowing because of oxygen defects. This study shed light on the modification of metal oxide nanostructures by EAB with a controlled band structure.

Abstract: Chirality plays a fundamental part in the activity of biological molecules and broad classes of chemical reactions, but detecting and quantifying it remains challenging. The spectroscopic methods of choice are usually circular dichroism and vibrational circular dichroism, methods that are forbidden in the electric dipole approximation. The resultant weak effects produce weak signals, and thus require high sample densities. In contrast, nonlinear techniques probing electric-dipole-allowed effects have been used for sensitive chiral analyses of liquid samples. Here we extend this class of approaches by carrying out nonlinear resonant phase-sensitive microwave spectroscopy of gas phase samples in the presence of an adiabatically switched non-resonant orthogonal electric field; we use this technique to map the enantiomer-dependent sign of an electric dipole Rabi frequency onto the phase of emitted microwave radiation. We outline theoretically how this results in a sensitive and species-selective method for determining the chirality of cold gas-phase molecules, and implement it experimentally to distinguish between the S and R enantiomers of 1,2-propanediol and their racemic mixture. This technique produces a large and definitive signature of chirality, and has the potential to determine the chirality of multiple species in a mixture.

Abstract: We use micro-Raman and photoluminescence (PL) spectroscopy at 300 K to investigate the influence of uniaxial tensile strain on the vibrational and optoelectronic properties of monolayer and bilayer MoS${}_{2}$ on a flexible substrate. The initially degenerate ${E}^{\ensuremath{'}}$ monolayer Raman mode is split into a doublet as a direct consequence of the strain applied to MoS${}_{2}$ through Van der Waals coupling at the sample-substrate interface. We observe a strong shift of the direct band gap of 48 meV/(% of strain) for the monolayer and 46 meV/% for the bilayer, whose indirect gap shifts by 86 meV/%. We find a strong decrease of the PL polarization linked to optical valley initialization for both monolayer and bilayer samples, indicating that scattering to the spin-degenerate $\ensuremath{\Gamma}$ valley plays a key role.

Abstract: Infrared absorption spectroscopy is a powerful biochemical analysis tool as it extracts detailed molecular structural information in a label-free fashion. Its molecular specificity renders the technique sensitive to the subtle conformational changes exhibited by proteins in response to a variety of stimuli. Yet, sensitivity limitations and the extremely strong absorption bands of liquid water severely limit infrared spectroscopy in performing kinetic measurements in biomolecules' native, aqueous environments. Here we demonstrate a plasmonic chip-based technology that overcomes these challenges, enabling the in-situ monitoring of protein and nanoparticle interactions at high sensitivity in real time, even allowing the observation of minute volumes of water displacement during binding events. Our approach leverages the plasmonic enhancement of absorption bands in conjunction with a non-classical form of internal reflection. These features not only expand the reach of infrared spectroscopy to a new class of biological interactions but also additionally enable a unique chip-based technology.

Abstract: Nitrogen-deficient graphitic carbon nitride (g-C3N4−x) was synthesized by a hydrothermal treatment using ammonium thiosulfate as an oxidant. The as-prepared photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption–desorption, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis (EA), electron paramagnetic resonance (EPR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) spectroscopy. The visible-light-driven photocurrent measurement was performed by several on–off cycles of intermittent irradiation. The photocatalytic activity of catalysts was evaluated by splitting water under visible-light irradiation (λ > 420 nm). Results demonstrated that the photoactivity of g-C3N4−x was enhanced greatly by the deficiency of the terminal amino species on the catalysts. The average H2 evolution rate on g-C3N4−x was 31.6 μmol h−1, which was ca. 3 times higher than that on pristine g-C3N4. It was revealed that the unique nitrogen-deficient structure of g-C3N4−x played an important role in broadened visible-light absorption and efficient electron–hole separation, mainly accounting for the improved photocatalytic activity.

Abstract: We perform radio-frequency dissociation spectroscopy of weakly bound 6Li2 Feshbach molecules using low-density samples of about 30 molecules in an optical dipole trap. Combined with a high magnetic field stability, this allows us to resolve the discrete trap levels in the radio-frequency dissociation spectra. This novel technique allows the binding energy of Feshbach molecules to be determined with unprecedented precision. We use these measurements as an input for a fit to the 6Li scattering potential using coupled-channel calculations. From this new potential, we determine the pole positions of the broad 6Li Feshbach resonances with an accuracy better than 7×10(-4) of the resonance widths. This eliminates the dominant uncertainty for current precision measurements of the equation of state of strongly interacting Fermi gases. As an important consequence, our results imply a corrected value for the Bertsch parameter ξ measured by Ku et al. [Science 335, 563 (2012)], which is ξ=0.370(5)(8).

Abstract: Transmission, reflection, refraction and scattering of Terahertz radiation.- Optical constants and dispersion relations in THz spectroscopy.- Scattering effects.- Converging Terahertz beam vs. plane wave.- Signal Processing - Wavelet Transform.- Signal Processing - Fractional Fourier transformation and spectrogram in signal processing of Terahertz pulses.- Terahertz Spectroscopy.- Crystalline and non-crystalline solids.- Liquids and Biomolecules.- Ellipsometry and active polarization control of Terahertz waves.- ATR sensing at terahertz frequencies.- Pump-probe spectroscopy.- Liquid crystals.- Waveguide spectroscopy.- Condensed matter physics.- Assignment of vibrational modes in crystalline materials.- On-chip pulsed Terahertz spectroscopy.- Nonlinear terahertz spectroscopy.- Terahertz Imaging.- Far-field / Near-field.- Biomedical Imaging.- Pharmaceutical imaging.- Terahertz tomography.- Security.- Artists' materials characterization.- Interesting Physics at Terahertz Frequencies.- Plasmonic structures.

Abstract: Vibrational sum-frequency generation (VSFG) spectroscopy is a powerful tool to study interfaces. Recently, multiplex heterodyne-detected VSFG (HD-VSFG) has been developed, which enables the direct measurement of complex second-order nonlinear susceptibility [χ(2)]. HD-VSFG has remarkable advantages over conventional VSFG. For example, the imaginary part of χ(2) [Imχ(2)] obtained with this interferometric technique is the direct counterpart to the infrared [Imχ(1)] and Raman [Imχ(3)] spectra in the bulk, and it is free from the spectral deformation inevitable in conventional VSFG [|χ(2)|2] spectra. The Imχ(2) signal is obtained with a sign that contains unambiguous information about the up/down orientation of interfacial molecules. Furthermore, HD-VSFG can be straightforwardly extended to time-resolved measurements when combined with photoexcitation. In this review, we describe the present status of experiments and applications of multiplex HD-VSFG spectroscopy, in particular with regard to the orientation...

Abstract: Layers of CH3NH3PbI3 are investigated by modulated surface photovoltage spectroscopy (SPV) during heating in vacuum. As prepared CH3NH3PbI3 layers behave as a p-type doped semiconductor in depletion with a band gap of 1.5 eV. After heating to 140 °C the sign of the SPV signals of CH3NH3PbI3 changed concomitant with the appearance of a second band gap at 2.36 eV ascribed to PbI2, and SPV signals related to charge separation from defect states were reduced after moderate heating.

Abstract: Phase-sensitive sum-frequency spectroscopy (SFS) allows the complete measurement of the complex spectra of surface nonlinear response coefficients. Similar to linear spectroscopy, the spectrum of the imaginary part of a surface response coefficient directly characterizes surface resonances without complication. This newly developed technique has greatly enhanced the capability of surface SFS and provides many new research opportunities for surface science. This article describes the experimental schemes and underlying theory for the technique and briefly reviews works that have clearly demonstrated its power.

Abstract: We report on spectroscopic observations covering most of the 475 BL Lacs in the 2nd Fermi LAT catalog of AGN. Including archival measurements (correcting several erroneous literature values) we now have spectroscopic redshifts for 44% of the BL Lacs. We establish firm lower redshift limits via intervening absorption systems and statistical lower limits via searches for host galaxies for an additional 51% of the sample leaving only 5% of the BL Lacs unconstrained. The new redshifts raise the median spectroscopic z from 0.23 to 0.33 and include redshifts as large as z=2.471. Spectroscopic redshift minima from intervening absorbers have ~ z= 0.70, showing a substantial fraction at large z and arguing against strong negative evolution. We find that detected BL Lac hosts are bright ellipticals with black hole masses M_\bullet ~ 10^{8.5-9}, substantially larger than the mean of optical AGN and LAT Flat Spectrum Radio Quasar samples. A slow increase in M_\bullet with z may be due to selection bias. We find that the power-law dominance of the optical spectrum extends to extreme values, but this does not strongly correlate with the gamma-ray properties, suggesting that strong beaming is the primary cause of the range in continuum dominance.

Abstract: [Abridged] After many attempts over more than a decade, high-resolution spectroscopy has recently delivered its first detections of molecular absorption in exoplanet atmospheres, both in transmission and thermal emission spectra. Targeting the combined signal from individual lines in molecular bands, these measurements use variations in the planet radial velocity to disentangle the planet signal from telluric and stellar contaminants. In this paper we apply high resolution spectroscopy to probe molecular absorption in the day-side spectrum of the bright transiting hot Jupiter HD 189733b. We observed HD 189733b with the CRIRES high-resolution near-infrared spectograph on the Very Large Telescope during three nights. We detect a 5-sigma absorption signal from CO at a contrast level of ~4.5e-4 with respect to the stellar continuum, revealing the planet orbital radial velocity at 154+4/-3 km s-1. This allows us to solve for the planet and stellar mass in a similar way as for stellar eclipsing binaries, resulting in Ms= 0.846+0.068/-0.049 Msun and Mp= 1.162+0.058/-0.039 MJup. No significant absorption is detected from H2O, CO2 or CH4 and we determined upper limits on their line contrasts here. The detection of CO in the day-side spectrum of HD 189733b can be made consistent with the haze layer proposed to explain the optical to near-infrared transmission spectrum if the layer is optically thin at the normal incidence angles probed by our observations, or if the CO abundance is high enough for the CO absorption to originate from above the haze. Our non-detection of CO2 at 2.0 micron is not inconsistent with the deep CO2 absorption from low resolution NICMOS secondary eclipse data in the same wavelength range. If genuine, the absorption would be so strong that it blanks out any planet light completely in this wavelength range, leaving no high-resolution signal to be measured.

Abstract: Introduction B. Imelik, J.C. Vendrine. Infrared Spectroscopy G. Coudurier, F. Lefebvre. Raman Spectroscopy E. Garbowski, G. Coudurier. Electronic Spectroscopy E. Garbowski, H. Praliaud. Nuclear Magnetic Resonance in Homogeneous and Heterogeneous Catalysis Y. Ben Taarit, J. Fraissard. Electron Paramagnetic Resonance M. Che, E. Giamello. Ferromagnetic Resonance L. Bonneviot, D. Olivier. Mossbauer Spectroscopy P. Bussiere. Auger Electron Spectroscopy J.C. Bertolini. Secondary Ion Mass Spectroscopy J. Grimblot, Abon. Ion Scattering Spectroscopy J. Grimblot, M. Abon. Applications of Neutron Scattering to Catalysis H. Jobic. X-Ray Absorption Spectroscopy B. Moraweck. Determination of the Atomic Structure of Solid Catalysis by X-Ray Diffraction G. Bergeret, P. Gallezot. Small Angle X-Ray Scattering A.J. Renouprez. Photo-Electron Spectroscopies J.C. Vendrine. Photo-Electron Diffraction and Surface Crystallography Y. Jugnet. 7 additional articles. Index.

Abstract: In this study we demonstrate that self-doping and surface plasmon resonance could endow a wide-band-gap ternary semiconductor BiOCl with remarkable visible light driven photocatalytic activity on the degradation of organic pollutants and photocurrent generation properties. The self-doped BiOCl with plasmonic silver modification was synthesized by a facile one-pot nonaqueous approach and systematically characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-visible diffuse reflectance spectra, electron spin resonance, and X-ray photoelectron spectroscopy. The photocurrent enhancement was found to be intimately dependent on the irradiation wavelength and matched well with the intensity of the absorption of the Ag nanoparticles. Reactive species trapping experiments and electron spin resonance spectroscopy with 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping adducts confirmed that more oxidative species could be generated from the photogenerated electrons due to the plasmon-excitation of the metallic Ag in the self-doped BiOCl with plasmonic silver modification, which is responsible for the great enhancement of photocatalytic activity and photocurrent. Surface photovoltage spectroscopy and time-resolved photoluminescence spectroscopy results revealed the transfer of plasmon-band-induced electrons from Ag nanoparticles into BiOCl and the acceleration effect of surface plasmon resonance-induced intense oscillating electric fields on this electron transfer. This study would not only provide direct evidence of plasmonic photocatalysis, but also shed light on the design of highly efficient metal–semiconductor composite photocatalysts.

Abstract: Free standing two-dimensional materials appear as a novel class of structures. Recently, the first colloidal two-dimensional heterostructures have been synthesized. These core/shell nanoplatelets are the first step toward colloidal quantum wells. Here, we study in detail the spectroscopic properties of this novel generation of colloidal nanoparticles. We show that core/shell CdSe/CdZnS nanoplatelets with 80% quantum yield can be obtained. The emission time trace of single core/shell nanoplatelets exhibits reduced blinking compared to core nanoplatelets with a two level emission time trace. At cryogenic temperatures, these nanoplatelets have a quantum yield close to 100% and a stable emission time trace. A solution of core/shell nanoplatelets has emission spectra with a full width half-maximum close to 20 nm, a value much lower than corresponding spherical or rod-shaped heterostructures. Using single particle spectroscopy, we show that the broadening of the emission spectra upon the shell deposition is not...

Abstract: Mott physics is characterized by an interaction-driven metal-to-insulator transition in a partially filled band In the resulting insulating state, antiferromagnetic orders of the local moments typically develop, but in rare situations no long-range magnetic order appears, even at zero temperature, rendering the system a quantum spin liquid A fundamental and technologically critical question is whether one can tune the underlying energetic landscape to control both metal-to-insulator and Neel transitions, and even stabilize latent metastable phases, ideally on a platform suitable for applications Here we demonstrate how to achieve this in ultrathin films of NdNiO3 with various degrees of lattice mismatch, and report on the quantum critical behaviours not reported in the bulk by transport measurements and resonant X-ray spectroscopy/scattering In particular, on the decay of the antiferromagnetic Mott insulating state into a non-Fermi liquid, we find evidence of a quantum metal-to-insulator transition that spans a non-magnetic insulating phase

Abstract: We report a disproportionation mechanism identified in the transformation of rod-like biicosahedral Au38(SCH2CH2Ph)24 to tetrahedral Au36(TBBT)24 nanoclusters. Time-dependent mass spectrometry and optical spectroscopy analyses unambiguously map out the detailed size-conversion pathway. The ligand exchange of Au38(SCH2CH2Ph)24 with bulkier 4-tert-butylbenzenethiol (TBBT) until a certain extent starts to trigger structural distortion of the initial biicosahedral Au38(SCH2CH2Ph)24 structure, leading to the release of two Au atoms and eventually the Au36(TBBT)24 nanocluster with a tetrahedral structure, in which process the number of ligands is interestingly preserved. The other product of the disproportionation process, i.e., Au40(TBBT)m+2(SCH2CH2Ph)24–m, was concurrently observed as an intermediate, which was the result of addition of two Au atoms and two TBBT ligands to Au38(TBBT)m(SCH2CH2Ph)24–m. The reaction kinetics on the Au38(SCH2CH2Ph)24 to Au36(TBBT)24 conversion process was also performed, and the ...

Abstract: Unmodified and Modified Silicas Interfacial Phenomena at a Surface of Nanosilica Silica gels, Aerogels, Silochrome, and Poly(methylsiloxane): Structural, Interfacial and Adsorption Characteristics, and Structure-Property Relationships Interfacial Phenomena at Surfaces of Structurally Ordered Silicas Thin Films and Other Moieties on Silica Supports Interfacial Phenomena at Surfaces of Mixed Oxides Mixed Nanooxides Porous Oxides as a Function of Morphology Structurally Ordered Oxides Nanocrystalline and Microcrystalline Materials Clays, Zeolites, and Other Natural Minerals Interfacial Phenomena at Surfaces of Carbon Materials Texture of Carbonaceous Materials and Chemical Shift of Adsorbed Molecules Activated Carbons Graphitized Carbons and Graphite Carbon Nanotubes Interfacial Phenomena at Carbon-Mineral Composites Carbon Blacks Carbonized Silicas and Mixed Oxides Interfacial Phenomena at Polymer Surfaces Natural Polymers: Cellulose, Starch, Chitosan, Hyaluronic Acid, and Others Synthetic Polymers Hydrogels and Cryogels Polymer-Nanooxide Systems Polymers in Confined Space of Pores Interactions of Biomacromolecules with Water, Organic Compounds, and Oxides, Polymers, and Carbon Adsorbents Proteins Proteins in Adsorbed State DNA Lipids Water Associated with Bio-Objects: Cells and Tissues Yeast Saccharomyces cerevisiae Cells Intracellular Water in Partially Dehydrated Bone Marrow Cells Freeze-Dried Bovine Gametes with Organic Additives Red Blood Cells Bone Tissue Muscular Tissues Intracellular Water and Cryopreservation Interaction of Seeds, Herbs, and Related Materials with Water and Nanooxides Recurring Trends in Adsorption, Spectroscopy, and Other Interfacial Experiments Methods Low-Temperature 1H NMR Spectroscopy Low-Temperature Nitrogen Adsorption Adsorption of Water and Organics Polymer and Protein Adsorption Infrared Spectroscopy Thermogravimetry Differential Scanning Calorimetry Auger Electron Spectroscopy Temperature-Programmed Desorption with Mass-Spectrometry Control Thermally Stimulated Depolarization Current Dielectric Relaxation Spectroscopy Ultraviolet-Visible Spectroscopy Rheometry Potentiometric Titration Photon Correlation Spectroscopy Adsorption of Metal Ions X-Ray Diffraction Raman Spectroscopy AFM, SEM, and TEM Quantum Chemistry Conclusions

Abstract: In this article, an increase of 1–2 orders of magnitude in laser-induced breakdown spectroscopy (LIBS) signals was obtained by depositing silver nanoparticles on metal samples. Nanoparticle-enhanced LIBS (NELIBS) was found to be a robust and flexible tool for the chemical analysis of metals because the sample emission signal did not appear to be affected much by the size and concentration of deposited nanoparticles (NPs) within the ranges of 10 nm for diameter and 1 order of magnitude for concentration. On the other hand, preliminary NELIBS tests on insulators and semiconductors did not show any significant enhancement with respect to conventional LIBS. In this article, we present a detailed investigation of the fundamental features of NELIBS spectra, in addition to some examples of analytical applications to the quantitative analysis of metal alloys.

Abstract: Coherently enhancing laser pulses in a passive cavity provides ideal conditions for high-order harmonic generation in a gas, with repetition rates around 100 MHz (refs 1,2,3). Recently, extreme-ultraviolet radiation with photon energies of up to 30 eV was obtained, which is sufficiently bright for direct frequency-comb spectroscopy at 20 eV (ref. 4). Here, we identify a route to scaling these radiation sources to higher photon energies. We demonstrate that the ionization-limited attainable intracavity peak intensity increases with decreasing pulse duration. By enhancing nonlinearly compressed pulses of an Yb-based laser and coupling out the harmonics through a pierced cavity mirror, we generate spatially coherent 108 eV (11.45 nm) radiation at 78 MHz. Exploiting the full potential of the demonstrated techniques will afford high-photon-flux ultrashort-pulsed extreme-ultraviolet sources for a number of applications in science and technology, including photoelectron spectroscopy, coincidence spectroscopy with femtosecond to attosecond resolution5,6 and characterization of components and materials for nanolithography7. Spatially coherent 11.45 nm radiation is produced by outcoupling the harmonics of cavity-enhanced nonlinearly compressed pulses from a Yb-based laser through a pierced cavity mirror. This technique may lead to high-photon-flux ultrashort-pulse extreme-ultraviolet sources for use in a wide range of applications.

Abstract: A series of boron ketoiminate derivatives that exhibited clear aggregation-induced emission (AIE) characteristics (in THF: Φ(PL)≤0.01; in the solid state: Φ(PL)=0.30-0.76) were prepared by the reactions of 1,3-enaminoketone derivatives with boron trifluoride-diethyl etherate. The structures and optical properties were investigated by UV-visible spectroscopy, photoluminescent (PL) spectroscopy, and X-ray single-crystal measurements. These results indicate that the AIE characteristics were derived from molecular motions of the boron-chelating rings with a boron-nitrogen (B-N) bond. Furthermore, the optical properties were controllable by steric hindrance of the substituted groups on the nitrogen atom.

Abstract: This is the first release of optical spectroscopic data of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project including 604 previously unpublished spectra of 93 SNe Ia. The observations cover a range of phases from 12 days before to over 150 days after the time of B-band maximum light. With the addition of 228 near-maximum spectra from the literature, we study the diversity among SNe Ia in a quantitative manner. For that purpose, spectroscopic parameters are employed such as expansion velocities from spectral line blueshifts and pseudo-equivalent widths (pW). The values of those parameters at maximum light are obtained for 78 objects, thus providing a characterization of SNe Ia that may help to improve our understanding of the properties of the exploding systems and the thermonuclear flame propagation. Two objects, namely, SNe 2005M and 2006is, stand out from the sample by showing peculiar Si II and S II velocities but otherwise standard velocities for the rest of the ions. We further study the correlations between spectroscopic and photometric parameters such as light-curve decline rate and color. In agreement with previous studies, we find that the pW of Si II absorption features are very good indicators of light-curve decline rate. Furthermore, we demonstrate that parameters such as pW2 (Si II 4130) and pW6 (Si II 5972) provide precise calibrations of the peak B-band luminosity with dispersions of 0.15 mag. In the search for a secondary parameter in the calibration of peak luminosity for SNe Ia, we find a 2σ-3σ correlation between B-band Hubble residuals and the velocity at maximum light of S II and Si II lines.

Abstract: Scanning transmission X-ray microscopy (STXM) has been used to investigate the chemical, electronic and structural nature of Co3O4 nanocrystals grown on single nitrogen-doped graphene sheets through spatially resolved X-ray absorption near edge structure (XANES) spectroscopy and chemical imaging. It has been found that Co3O4 nanocrystals grown on N-doped graphene were partially reduced via Co3+(Oh) to Co2+(Oh), and the reduction varies spatially on and among individual Co3O4 nanocrystal-graphene sheets. Nitrogen sites on graphene have been shown to be major and important anchoring sites for Co3O4 nanocrystals in addition to the carbon and possibly oxygen sites. Macroscopic XANES of Co L-edge and K-edge were also measured to confirm the localized STXM result that Co3+ was partly reduced in the hybrid material. These insights should account for the superior performance of the covalently coupled Co3O4/graphene hybrid in energy related applications.