Magnesium is a key component used by many organisms in biomineralization. One role for magnesium stabilizing an otherwise unstable amorphous calcium carbonate (ACC) phase. The way which this stabilization achieved unknown. Here, we address question studying the chemical environment around biogenic and synthetic ACCs using Mg K-edge X-ray absorption spectroscopy (XAS). We show that although short-range structure ion different various minerals studied, they all involve shortening of Mg−O bond...

The adsorption of Na on Al(111) at room temperature has been studied by surface extended x-ray-absorption fine-structure (SEXAFS) experiments as well parameter-free calculations. For coverages ${\mathrm{\ensuremath{\Theta}}}_{\mathrm{Na}}$=0.16--0.33, the SEXAFS analysis shows that atoms occupy an unusual six-fold-coordinated substitutional site. Na-Al bond length is determined 3.31 \AA{}, consistent with metallic bonding. Ab initio density-functional-theory calculations for several...

Tweaking the properties of carbon nanotubes is a prerequisite for their practical applications. Here, we demonstrate fine tuning electronic single-wall via filling with ferrocene molecules. The evolution bonding and charge transfer within tube demonstrated chemical reaction filler ending up as secondary inner tube. nature interpreted well density functional theory. This work gives direct observation fine-tuned continuous amphoteric doping nanotubes.

Luminescent Cu(I) complexes are interesting candidates as dopants in organic light-emitting diodes (OLEDs). However, open questions remain regarding the stability of such solution and therefore their suitability for processing. Since emission behavior emitters often drastically differs between bulk thin film samples, it cannot be excluded that changes partial decomposition or formation alternative emitting compounds upon processing responsible. In this study, we present three particularly...

Hydrogenation of 6H–SiC (0001) and (0001̄) is achieved by high-temperature hydrogen treatment. Both surfaces show a low-energy electron diffraction pattern representative unreconstructed extremely high crystallographic order. On SiC(0001), hydrogenation confirmed the observation sharp Si–H stretching modes. The absence surface band bending for n- p-type samples indicative electronically passivated with densities charged states in gap below 7×1010 cm−2 1.7×1012 type samples, respectively....

The excitement of nano-test-tube chemistry in a single-walled carbon nanotube is exemplified our study on electron doping nanotubes. Electron through the 1D van Hove singularity nanotubes realized via chemical reaction an encapsulated organocerium compound, CeCp3. decomposition CeCp3 inside increases level and greatly enhances density conduction electrons. transition cerium encapsulating semiconducting tubes to metallic results enhanced screening photoexcited core hole potential. This fact...

We have studied enantiospecific differences in the adsorption of (S)- and (R)-alanine on Cu{531}R using low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy, near edge absorption fine structure (NEXAFS) spectroscopy. At saturation coverage, alanine adsorbs as alaninate forming a p(1 × 4) superstructure. LEED shows significantly higher degree long-range order for S than R enantiomer. Also carbon K-edge NEXAFS spectra show between variations π resonance when linear...

The application of new polymer materials for organic solar cells requires a detailed understanding the orientation and electronic properties system because these have dramatic effect on device performance efficiency. films were prepared by doctor blade casting, simple preparation route from solution. We study low band gap polymers poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT)...

Indazolium trans-[tetrachlorobis(1H-indazole)ruthenate(III)] (1, KP1019) and its analogue sodium (2, KP1339) are promising redox-active anticancer drug candidates that were investigated with X-ray absorption near edge structure spectroscopy. The analysis was based on the concept of coordination charge ruthenium model compounds representing possible coordinations oxidation states in vivo. 1 citrate saline buffer (pH 3.5) carbonate 7.4) at 37 °C for different time intervals. Interaction...

X-ray absorption (XAS) and core level photoelectron spectroscopy are versatile tools to site selectively study the unoccupied density of states bonding environment. Hence, they widely applied single-wall carbon nanotubes (SWCNTs) as archetypes one-dimensional solids. However, their van Hove singularities (vHs's) were indiscernible. In this paper, we unravel vHs in XAS response SWCNT. These results pave way toward a conclusive understanding interplay between charge transfer hybridization...

We present a high-resolution photoelectron spectroscopy investigation of condensed films benzene, naphthalene, anthracene, tetracene, and pentacene. High spectroscopic resolution systematic variation the molecular size allow detailed analysis fine structures. The line shapes C 1s main lines are analyzed with respect to different contributions inhomogeneous broadening, vibronic coupling, chemical shifts. shake-up satellite spectra reveal trends, which give insight into charge redistribution...

The adsorption of Na on Al(100) at 140 and 300 K has been studied by surface extended x-ray-absorption fine-structure experiments. An analysis the measurements shows that local geometry in c(2\ifmmode\times\else\texttimes\fi{}2)-Na phases formed each temperature is completely different. At atoms occupy fourfold hollow sites, whereas a model favored where lie beneath reconstructed Al layer. Warming to causes an irreversible transformation low-temperature structure room-temperature structure.

The properties of heterogeneous interfaces are modified essentially by the presence nanoparticles. We provide a model and give spectroscopic evidence that nanoscale clusters exist which have metallic core shell an almost perfect oxide. Such produce large dipole moment manifests itself as shifts in levels seen photoelectron spectroscopy, well non-Ohmic rectifying behavior device electrical properties.

Measurements of polarization and temperature dependent soft x-ray absorption have been performed on Na_xCoO_2 single crystals with x=0.4 x=0.6. They show a deviation the local trigonal symmetry CoO_6 octahedra, which is independent in range between 25 K 372 K. This was found to be different for Co^{3+} Co^{4+} sites. With help cluster calculation we are able interpret Co L_{23}-edge spectrum find doping energy splitting t_{2g} e_g levels (10Dq) Na_xCoO_2.

We study charge delocalization and polarization effects in organic thin films by comparing surface- bulk-sensitive, high-resolution $\mathrm{C}\phantom{\rule{0.2em}{0ex}}1\mathrm{s}$ photoemission data using tunable synchrotron radiation. In three cases, perylene-tetracarboxylicacid-dianhydride, coronene, metal-free phthalocyanine, no surface core level shifts are observed (upper limit $100\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$). This unexpected finding shows that effects, hence...

The electronic properties of matter are on the nanometer scale strongly influenced by its local environment. site-dependent in composites semiconducting and metallic at heart establishing molecular electronics. Our combined theoretical experimental investigations comprise first-principles calculations, resonant x-ray absorption as well core-level valence-band photoemission pristine potassium intercalated bundles mixtures single-wall carbon nanotubes. We present a coherent picture...

We report on a detailed study of the electronic properties newly synthesized trimetal nitride fullerene ${\mathrm{Dy}}_{3}\mathrm{N}@{\mathrm{C}}_{80}$ (isomer I) using high-energy spectroscopies as probes. From ultraviolet photoemission and $\mathrm{C}\phantom{\rule{0.2em}{0ex}}1s$ absorption we observe that occupied unoccupied structures cage are very similar to those other fullerenes hence both spectra exhibit narrow corresponding molecular states ${\mathrm{C}}_{80}$ with ${I}_{h}$...