Can X(3872) be a JP=2- Tetraquark State?

In this article, we test the nature of X(3872), which is assumed to be a P-wave [cq]-scalar-diquark [cq]-axial-vector-antidiquark tetraquark state with J^P=2^-. The interpolating current representing the J^P=2^- state is proposed. Technically, contributions of the operators up to dimension six are included in the operator product expansion. The mass obtained for such state is m_2-=(4.38? 0.15) GeV. We conclude that it is impossible to describe the X(3872) structure as J^P=2^- tetraquark state.     

Bulk terminated NaCl(111) on aluminum: a polar surface of an ionic crystal?

Atomically resolved scanning tunneling microscopy reveals the existence of triangular (111) bulk terminated NaCl islands. The islands can be grown by subsequent adsorption of Na and Cl2 on Al(111) and Al(100) or by conversion of stoichiometric NaCl(100) islands to NaCl(111) via additional Na adsorption. The NaCl(111) islands have Na-Cl-Na sandwich structure. Ab initio calculations of the electronic structure of these islands show that each of the Na atoms carries half a positive elementary charge, leaving the islands neutral and explaining the existence of an otherwise unstable surface.     

What can a heavy U(1)B-L Z'boson do to the muon(g-2)u anomaly and to a new Higgs boson mass?

The minimal U(1)B_L extension of the Standard Model(B-L-SM)offers an explanation for neutrino mass generatio n via a seesaw mechanism;it also offers two new physics states,namely an extra Higgs bos on and a new Z'gauge boson.The emerge nee of a second Higgs particle as well as a new Z'gauge boson,both lin ked to the breaking of a local U(1)B_L symmetry,makes the B-L-SM rather constrained by direct searches in Large Hadron Collider(LHC)experiments.We investigate the phenomenological status of the B-L-SM by confr on ting the new physics predictions with the LHC and electroweak precision data.Taking into account the current bounds from direct LHC searches,we demonstrate that the prediction for the muon(g-2)u anomaly in the B-L-SM yields at most a contribution of approximately 8.9×10^-12,which represents a tension of 3.28 standard deviations,with the current 1σuncertainty,by means of a Z'boson if its mass is in the range of 6.3 to 6.5 TeV,within the reach of future LHC runs.This means that the B-L-SM,with heavy yet allowed Z‘bos on mass range,in practice,does not resolve the tension between the observed anomaly in the muon(g-2)u and the theoretical prediction in the Standard Model.Such a heavy Z'boson also implies that the minimal value for the new Higgs mass is of the order of 400 GeV.     

Au and Cu Atoms on NaCl(001): a single-atom based memory device prototype?

We present a first-principle study of gold and copper atoms adsorbed in NaCl(001) surfaces. Motivated by a recent STM experiment on this subject, the electronic and magnetic properties of Au and Cu atoms are investigated, as well as the modifications in these properties under charge injection. Similarities of these systems and the corresponding isolated atom are exploited. A discussion about the possibility of applying the studied systems on high-density memory devices is addressed.     

Charge transfer between isomer domains on n(+)-doped Si(111)-2?×?1: energetic stabilization

Domains of different surface reconstruction-negatively or positively buckled isomers-have been previously observed on highly n-doped Si(111)-2?×?1 surfaces by angle-resolved ultraviolet photoemission spectroscopy and scanning tunneling microscopy/spectroscopy. At low temperature, separate domains of the two isomer types are apparent in the data. It was argued in the previous work that the negative isomers have a lower energy of their empty surface states than the positive isomers, providing a driving force for the formation of the negative isomers. In this work we show that the relative abundance of these two isomers shows considerable variation from sample to sample, and it is argued that the size of the isomer domains is likely to be related to this variation. A model is introduced in which the electrostatic effect of charge transfer between the domains is computed, yielding total energy differences between the two types of isomer. It is found that the transfer of electrons from domains of positive isomers to negative ones leads to an energetic stabilization of the negative isomers. The model predicts a dependence of the isomer populations on doping that is in agreement with most experimental results. Furthermore, it accounts, at least qualitatively, for the marked lineshape variation from sample to sample observed in photoemission spectra.     

Portable optical water-and-oil analyzer based on a mid-IR (1.6–2.4 μm) optron consisting of an LED array and a wideband photodiode

An optical method for measuring the water and oil content using mid-IR (1.6–2.4 μm) LEDs and a wideband photodiode is suggested for the first time. This method is developed based on the absorption spectra of pure water, dewatered oil, and water—oil emulsions (cut oil) with different content of water and uses 10 types of LEDs in the spectral range 1.6–2.4 μm. It is shown that pure water heavily absorbs the LED radiation in the spectral range 1.85–2.05 μm, oil absorbs in the range 1.67–1.87 μm, and the LED radiation with a maximum at 2.20 μm is equally weakly absorbed by water and oil. An optical cell of the water-and-oil analyzer is designed on the basis of a three-element diode array with radiation maxima at 1.65 (detection of oil), 1.94 (detection of water), and 2.2 μm (reference signal) wideband photodiode covering the spectral range 1.3–2.4 μm. A calibration curve is derived that represents the dependence of the water concentration in oil on the amplitude of the reduced signal obtained by processing three signals from the LEDs. This optical method of measuring the water content in oil underlies a portable analyzer making possible online measurements directly in an oil well.     

Theoretical studies on the structures and absorption spectra of–C n R2n+1(R = H,F; n = 1, 2) substituted 5-(2-pyridyl) pyrazolate boron complexes

The molecular structures, electronic structures and absorption characters of–CH₃,–C₂H₅,–CF₃,–C₂F₅ substituted 5-(2-pyridyl) pyrazolate boron complexes were presented by density functional theory (DFT). The ground state structures of the title complexes were optimised at B3LYP/6-31G* level. In addition, a time dependent density functional theory (TD-DFT) method is applied to investigate the properties of absorption spectra and electronic transition mechanism which were based on the ground state geometries. The results show that the chemical bond formed between nitrogen in the pyridyl ring and boron can be attributed to coordination effect. The boron centre has a typical tetrahedral geometry with the adjacent atoms. The calculated absorption wavelengths for–CF₃,–C₂F₅ substituted 5-(2-pyridyl) pyrazolate boron complexes are in good agreement with the experimental data.     

Structure determination of Ni(110)-(2 × 3)-N by use of SEXAFS measurements: on-surface and sub-surface sites on a pseudo-(100) reconstructed surface

Surface-extended X-ray-absorption fine-structure measurements have been performed on the Ni(110)-(2 × 3)-N system. The data are consistent with a model in which nitrogen chemisorbs on a pseudo-(100) reconstructed and largely corrugated surface with a nearest-neighbour N-Ni bond length of 1.86 ± 0.03 Å. The corrugation results in two raised and two lowered [11̄0] Ni rows which are not uniformly distributed in the [001] direction. Nitrogen chemisorbs in four-fold hollow sites slightly (0.19Å) above the lowered Ni rows and in pseudo-four-fold hollow sites slightly (0.38 Å) below the plane defined by a raised and a lowered Ni row. In both sites N is equidistantly bonded to Ni atoms in the second layer. Structural models with long-bridge adsorption sites can be safely excluded.     

Thermal evolution of Co on the coexisting Ag/Ge(111)- \sqrt 3 \times \sqrt 3 and Ag/Ge(111)-4?×?4 phases

This study explores the suitability of microfibrillated cellulose (MFC) films as a substrate for printing electrically conductive structures and multilayer electronic structures such as organic field effect transistors. Various MFC qualities were tested, including mechanically produced MFC, 2,2,6,6-tetramethylpiperidinyl-1-oxyl pre-treated MFC and carboxymethylated-MFC. The films differed significantly with respect to the surface structure. In addition, the carboxymethylated-MFC films were surface modified with hexamethyldisilazane (HMDS) to reduce the water-wettability of the films, and thus, improve the print resolution of the inkjet-printed silver (Ag) nanoparticles. The Ag-particles (diameter?<?50?nm) were printed on the HMDS-modified films, which were mainly composed of nanofibrils with diameters <20?nm. The effect of surface roughness and surface chemical characteristics on the ink spreading and print resolution of the Ag-structures was explored. It was demonstrated that organic transistors operating at low voltages can be fabricated on nano-engineered MFC films.     

Influence of isotopic substitution on spectral and structural parameters of an isolated [F(HF)<Subscript>2</Subscript>]— complex. Substitution of a proton by a kaon and a triton

This paper continues the theoretical study (see V. P. Bulychev and M. V. Buturlimova, J. Mol. Struct. 928, 32 (2009)) of the isotopic effects in the H-bonded anionic complex [F(HF)₂]-. Isotopomers of the complex with significant differences between the masses of the light atoms are considered. The four-dimensional anharmonic vibrational problem are solved by the variational method for the symmetric complex [F(KaF)₂]-, in which both protons are substituted by a positive kaon (positive K-meson), and for the asymmetric complex [FKaFTF]-. Variables related to the changes in the lengths of molecular fragments LF (L = Ka and T) and the distances between the F^- anion and the centers of mass of LF are used as the vibra-tional coordinates. The potential energy surfaces are calculated in the MP2/6-311++G(3df,3pd) approximation taking into account the basis set superposition error. The vibrational energy levels, frequencies, and absolute intensities for spectral transitions are determined. To study the isotope effect on the geometrical parameters of the complex, the values of internuclear separations and the asymmetry parameter of the F^-…L-F bridge averaged over the ground state and several excited vibrational states are calculated, as well as their standard deviations. The calculated results are compared to the data obtained previously for the symmetric complexes [F(HF)₂]^-, [F(DF)₂]^-, and [F(TF)₂]^-.     

Aromaticity on the edge of chaos: an Ab initio CCSD(T) study of the bimodal balance between aromatic and non-aromatic structures for 10-π-diheterocins and heteronins

CCSD(T) coupled cluster ab initio SCF-MO calculations for 10-π-heteroannulenes reveal a range of potential surface characteristics, ranging from single-minimum aromatic planar species to triple-minimum systems involving both planar-aromatic and the two enantiomers of a C₂ symmetric non-planar non-aromatic species. For the specific case of 1,4-dioxocine, the existence of barriers separating the three minima is attributed to an anti-aromatic Möbius-like transition state connecting the two equilibrium forms.     

Growth of nanosize Ag dots with uniform height on?a?Si(111)-7×7-C2H5OH surface, and their electronic properties

C₂H₅OH adsorbs by dissociating on Si-adatom/Si-rest atom pair sites on Si(111)-7×7 surfaces. A half of six Si adatoms and three Si rest atoms are changed to Si-OC₂H₅ and Si-H in every half unit cell at the saturation. When an Ag atom was deposited on this surface, it was stabilized on an intact Si adatom remained in the half unit cell and it did not migrate by hopping. With the increasing number of deposited atoms, uniform height with ca. 5-nm size Ag dots were grown in wide area. A similar growth mode was observed by depositing Ga and Zn on this surface. We deduced that the uniform height growth of 5-nm dots may be given by a layer-by-layer growth of dots in the natural templates composed of six half unit cells. Scanning tunneling spectroscopy indicated that one-monolayer Ag dots had nonmetallic energy gap of ca. 2.2 V at the Fermi level, but the energy gap became narrower with the increasing number of layers and became metallic at eight or nine layers.     

The geometries of coadsorbate layers of O and H on Ru(0 0 1): How well can quantitative LEED see hydrogen atoms?

Using a CCD LEED system for the collection of IV data with low beam damage, and full dynamical as well as tensor LEED calculations, we have determined the geometries of the (2 × 2)-(O + 3H) and the (2 × 2)-(O + H) coadsorbate structures on Ru(0 0 1). We show that here quantitative LEED can locate the H atoms very well. Not only their sites (hcp in the first, fcc in the second case), but also the Ru–H spacings and changes in the first two substrate layers are clearly determined. We argue that this success is due to the relatively large data range and to the smaller H mobility compared to pure H layers caused by their repulsive lateral interactions with the oxygen atoms.     

C60 submonolayers on the Si(1 1 1)-(7 × 7) surface: Does a mixture of physisorbed and chemisorbed states exist?

We have carried out a combined X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy(UPS), and scanning tunnelling microscopy (STM) study of the C₆₀-Si(1 1 1) interaction where the XPS/UPS spectrometer and STM are integrated on a single UHV system. This enables a direct comparison of the XPS/UPS spectra with the STM data and eliminates any uncertainty in C₆₀ coverage measurements. X-ray standing wave measurements and density functional theory calculations have been used to support and interpret the results of the XPS/UPS/STM experiments. Our data conclusively rule out models of C₆₀ adsorption which involve a mixture of physisorbed and chemisorbed molecules [K. Sakamoto, et al., Phys. Rev. B 60 (1999) 2579]. Instead, we find that all molecules, up to 1 monolayer coverage, bond to the surface via Si–C bonds which are predominantly of covalent character.     

STM characterization of size-selected V1, V2, VO,and VO2 clusters on a TiO2(110)-(1 × 1) surface at room temperature

We use ultra-high vacuum scanning tunneling microscopy (UHV–STM) to probe, at the atomic level, the structure of mass-selected isolated V₁, V₂, VO and VO₂ clusters deposited on rutile TiO₂(110) by ion soft landing. All four species interact differently with the TiO₂ surface and the ultimate binding site and configuration strikes a balance between the gas-phase structure and the ligation of this cluster by the TiO₂ surface. Our results show that vanadium atoms prefer to bind in the upper threefold hollow sites on the surface and have a slight tendency to pair along the [1–10] direction, while vanadium dimers bind to the surface oriented along the [001] direction exclusively. VO clusters bind with the vanadium atom in the upper threefold hollow site and with the oxygen atom bound to an adjacent fivefold coordinated Ti atom (5c-Ti). The VO₂ cluster also binds with the vanadium atom in the upper threefold hollow site and with both oxygen atoms bound to adjacent 5c-Ti atoms or with only one oxygen bound to the surface and the other directed out of the plane of the surface.     

Corrigendum to: Discussion on Active aeroelastic control of 2-D wing-flap systems operating in an incompressible flowfield and impacted by a blast pulse by Librescu et al., Journal of Sound and Vibration 283 (3–5) (2005) 685–706 [Journal of Sound Vibration 332 (13) (2013) 3351–3358]

This corrigendum supplies a corrected statement of an equation in our discussion paper recently appearing in Journal of Sound and Vibration 332 (13) (2013) 3351–3358. This equation concerns the control input coefficient matrix of the state-space representation of the aeroelastic system. It illustrates the influence of the error in the calculation of aeroelastic impulse, step, and ramp responses, as well as demonstrating the accuracy and legitimacy of the present model in comparison to well-established literature data.