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Inelastic electron tunneling spectroscopy (IETS) performed with the scanning tunneling microscope (STM) has been deemed as the ultimate tool for identifying chemicals at the atomic scale. However, direct IETS-based chemical analysis remains difficult due to the selection rules that await a definite understanding. We present IETS simulations of single formate and benzoate species adsorbed in the same upright bridge geometry on a (111)-cleaved Cu surface. In agreement with measurements on a related substrate, the simulated IET-spectra of formate/Cu(111) clearly resolve one intense C-H stretching mode whatever the tip position in the vicinity of the molecular fragment. At variance, benzoate/Cu(111) has no detectable IET signal. The dissimilar IETS responses of chemically related molecules-formate and benzoate adsorbates-permit us to unveil another factor that complements the selection rules, namely the degree of the vacuum extension of the tunneling active states perturbed by the vibrations. As a consequence, the lack of a topmost dangling bond orbital is entirely detrimental for STM-based inelastic spectroscopy but not for STM elastic imaging. [ABSTRACT FROM AUTHOR]

Presents a theoretical study of the electronic processes occurring in collisions of hydrogen molecular ions on an aluminum surface. Molecular dissociation induced by electronic transitions; Channels of the neutralization process; Auger deexcitation process of the b state; Efficient quenching of the excited state; Reduction in the molecular dissociation probability.

Highlights • Transport calculation for a well defined system that can be easily compared with other numerical approaches, and explores the effect of local basis sets, saying how we can improve the description of STM images going beyond typical approaches based on Tersoff–Hamman-like methods. Graphical abstract Abstract The description of tunneling currents from non-equilibrium electronic structure using localized basis sets is very demanding. The problem stems from the lack of accuracy to describe evanescent waves in the tunneling barrier when the basis set is limited. The same problem exists for extended basis sets such as planewaves, except because increasing the number of planewaves simply improves the description. With local basis sets several strategies exist for improving the tunneling scattering structure. Here, we explore them and compare with previous work. Our conclusion is that using ghost atoms in self-consistent codes such as Transiesta is a valid and accurate way of performing tunneling calculations. However, attention must be paid not to break the symmetry of the transmission channels by incorrect inclusion of the ghost atom and to perform a fully self-consistent calculation to avoid ghost transmissions. [ABSTRACT FROM AUTHOR]

The time evolution of a model quantal magnetic moment proportional to an angular momentum, S , is studied and compared to that of a classical magnetic moment. The presence of an anisotropy quadratic term in the Hamiltonian makes classical and quantal behaviours qualitatively different for small values of the angular momentum, S . When S is increased, the classical behaviour is retrieved for a finite amount of time, even in the presence of magnetic anisotropy terms; however, in general, this limit is only reached for very large S values. The classical vs quantal behaviour is discussed in terms of three characteristic times of the system: the classical precession time, the quantal revival time and the spreading time. This allows showing that the closer to equilibrium the initial conditions are, the easier the classical limit is reached. [ABSTRACT FROM AUTHOR]

When the external magnetic field applied to a ferromagnetically coupled atomic chain is reversed suddenly, the magnetization of the chain switches, due to the reversal of all the atomic magnetic moments in the chain. The quantum processes underlying the magnetization switching and the time required for the switching are analyzed for model magnetic chains adsorbed on a surface at 0 K. The sudden field reversal brings the chain into an excited state that relaxes towards the system ground state via interactions with the substrate electrons. Different mechanisms are outlined, ranging from the global stepwise rotation of the chain macrospin induced by spin-flip collisions with substrate electrons in the pure Heisenberg chain (Néel-Brown process) to a correlation-mediated direct switching process in the presence of strong magnetic anisotropies in short chains (the global spin of the chain reverses in a single electron interaction). The processes for magnetization switching induced by electrons tunneling from a scanning tunneling microscope tip are also analyzed. [ABSTRACT FROM AUTHOR]

The lifetime of magnetic excitations in finite ID-supported Heisenberg chains of magnetic atoms is studied theoretically for a model system formed of S = j spins. Both ferromagnetic and antiferromagnetic cases are considered as well as open chains and rings of atoms. Different chain lengths are considered allowing extrapolation to infinite chains. All the excited magnetic states in the finite chains and rings are studied, not only the spin-wave mode. The magnetic excitations decay by electron-hole pair creation in the substrate. As the main result, for all the systems considered, the decay rate appears to vary approximately proportionally to the excitation energy of the state, with a proportionality constant independent of the strength of the Heisenberg exchange term. In certain finite systems, a stable state is evidenced at low energy, associated with a special spin coupling structure. [ABSTRACT FROM AUTHOR]

Excitation of finite size chains of magnetic spin-1/2 atoms adsorbed on a surface by tunneling electrons from a scanning tunneling microscope is studied theoretically in the case of a frustrated ferromagnetic structure of the chain. The magnetic excitation processes are described using the strong coupling approach from Lorente and Gauyacq Phys. Rev. Lett. 103 256802 (2009)]. Varying the exchange-coupling parameters, the chain length and the strength of an applied magnetic field generates a broad variety of magnetic structures in the chain. The links between these various structures and the excitation processes by tunneling electrons are presented, together with a discussion on how the magnetic structure of a chain could be inferred from an inelastic electron tunneling experiment. Extrapolation of the finite size calculations to infinite chains leads to a discussion of the characteristics of the spin waves that can be excited by tunneling electrons in these frustrated magnetic systems. [ABSTRACT FROM AUTHOR]

Excitation of finite chains of magnetic atoms adsorbed on a surface by tunneling electrons from a scanning tunneling microscope tip is studied using a Heisenberg Hamiltonian description of the magnetic couplings along the chain and a strong coupling approach to inelastic tunneling. The excitation probability of the magnetic levels is very high and the excitation spectra in chains of different lengths are very similar. The excitations in finite chains can be considered as spin waves quantized in the finite object. The energy and momentum spectra of the spin waves excited in the idealized infinite chain by tunneling electrons are determined from the results on the finite chains. Both ferromagnetic and antiferromagnetic couplings are considered, leading to very different results. In particular, in the antiferromagnetic case, excitations linked to the entanglement of the chain ground state are evidenced. [ABSTRACT FROM AUTHOR]

Abstract: Novel two-electron processes are proposed for the desorption of a single ammonia molecule (NH3) chemisorbed on a Cu(100) surface as induced by an inelastic tunneling current with the scanning tunneling microscope. According to density functional theory calculations, it is found that a single excitation of the high-frequency (HF) symmetric N–H stretch mode (408meV) can induce the lateral translation of NH3 via the transfer of energy to the frustrated-translation mode. In order to overcome the 600meV desorption barrier, a double excitation of the symmetric N–H stretch mode is needed. A rate equation approach is employed to study different elementary processes for NH3 desorption following the double excitation of the N–H mode by two tunneling electrons. After the double excitation of the HF mode, two possible reaction paths are possible: either the HF mode de-excites once creating and intermediate state with excited HF and reaction-coordinate (RC) modes that after decay leads to desorption, or the HF mode completely de-excites in the RC mode leading to desorption. In the first scenario, when the vibrational damping rate of the RC mode is lower than that of the HF mode, the intermode coupling from the excited state activates the RC mode above the barrier with help of energy transfer from the HF mode. Both, mode decay and intermode coupling, are made possible by energy transfer to the continuum of electronic excitations of the metallic surface: the electron–hole pair excitations. [Copyright &y& Elsevier]

The electronic current originating in a scanning tunneling microscope (STM) can be used to induce motion and desorption of adsorbates on surfaces. The manipulation of CO molecules on noble metal surfaces is an academic case that has received little theoretical attention. Here, we do thorough density functional theory calculations that explore the chemisorption of CO on Cu(110) and Ag(110) surface and its vibrational properties. The STM induced dynamics are explored after excitation of the highest lying mode, the C–O stretch. In order to give a complete account of this dynamics, the lifetime of the different CO modes is evaluated (by only including the mode decay into electronic excitations of the host surface) as well as the intermode coupling. Hence, after excitation of the stretch mode, the lower-energy modes are populated via intermode coupling and depopulated by electron-hole excitations. This study reveals the intrinsic features of the STM induced motion of CO on Cu(110) and Ag(110). [ABSTRACT FROM AUTHOR]

The scanning tunnelling microscope (STM) can induce molecular vibrations. This is detected by changes in the tunnelling conductance as the bias voltage matches a vibrational excitation threshold. Vibrational spectroscopy is available for a unique molecule. Nevertheless, the experimental results present several challenges: few modes are detected, certain symmetries are dominant, and site and conformation properties affect the detection. Despite these difficulties, this technique is proving to be of the uttermost importance in the analysis of molecular adsorbates and in their manipulation. We present a general theory that can predict the outcome of STM induced vibrational spectroscopy. The above challenges are analysed and quantitative results are then shown. [ABSTRACT FROM AUTHOR]

The selective excitation of molecular vibrations provides a means to directly influence the speed and outcome of chemical reactions. Such mode-selective chemistry has traditionally used laser pulses to prepare reactants in specific vibrational states to enhance reactivity or modify the distribution of product species. Inelastic tunnelling electrons may also excite molecular vibrations and have been used to that effect on adsorbed molecules, to cleave individual chemical bonds and induce molecular motion or dissociation. Here we demonstrate that inelastic tunnelling electrons can be tuned to induce selectively either the translation or desorption of individual ammonia molecules on a Cu(100) surface. We are able to select a particular reaction pathway by adjusting the electronic tunnelling current and energy during the reaction induction such that we activate either the stretching vibration of ammonia or the inversion of its pyramidal structure. Our results illustrate the ability of the scanning tunnelling microscope to probe single-molecule events in the limit of very low yield and very low power irradiation, which should allow the investigation of reaction pathways not readily amenable to study by more conventional approaches. [ABSTRACT FROM AUTHOR]

Light emission during the interaction of slow singly-charged clusters with solid surfaces is studied theoretically. More precisely, we consider positive ions of Agn clusters (n = 1...5) impinging on silver surfaces. In such systems, the charge transfer process involved during the cluster-surface interaction is mainly resonant capture. However, photon emission due to radiative capture is also a possible charge transfer channel. Our simple theoretical model including both processes allows us to calculate the light spectra and the total photon yield for the different cluster sizes, n. Our results show that light emission strongly depends on the electronic level dynamics of the clusters in front of the surface, providing a tool for electronic structure analysis of atoms, clusters and solid surfaces. [ABSTRACT FROM AUTHOR]

We discuss how the excitation of high-frequency modes in adsorbed molecules may result in motion (e.g., rotation, translation, or dissociation) of the molecules. Our study is based on rate equations and considers one- and two-vibrational excitation processes, corresponding to linear and quadratic dependences of the reaction rate on the tunneling current in the case the scanning tunneling microscopy is used to excite the vibrations (inelastic tunneling). From the results reported in this paper it should be possible to obtain intramolecular transition rates directly from the experimental data, and gain some understanding on how these important quantities depend on the modes involved and on the substrate. [ABSTRACT FROM AUTHOR]

We report on a theoretical study of the lifetime of the first excited state of spin chains made of an odd number of Fe atoms on Cu2N/Cu(100). Yan, Choi, Burgess, Rolf-Pissarczyk, and Loth [Nat. Nanotech. 10, 40 (2015)] recently observed very long lifetimes in the case of Fe3 chains. We consider the decay of the first excited state induced by electron-hole pair creation in the substrate. For a finite magnetic field, the two lowest-lying states in the chain have a quasi-Néel state structure. Decay from one state to the other strongly depends on the degree of entanglement of the local spins in the chain. The weak entanglement in the chain accounts for the long lifetimes that increase exponentially with chain length. Despite their apparently very different properties, the behavior of odd and even chains is governed by the same kind of phenomena, in particular entanglement effects. The present results account quite well for the lifetimes recently measured by Yan et al. on Fe3. [ABSTRACT FROM AUTHOR]

An abstract of the article "Area of urogenital hiatus and severity of genital prolapse: Is there any correlation?" by N. Lorente and others is presented.

Purpose of investigation: To analyze which are the risk factors in developing multicentric lesions of lower genital tract. Materials and Methods: A prospective study of 1,011 patients was conducted at the low genital tract pathology clinic of Sant Joan de Deu Hospital between 2003-2011. A complete assessment of cervix, vagina, and vulva was carried out including HPV-DNA testing, cytology study, colposcopy, and biopsy in case of atypical findings. The statistical analysis was done with SPSS v.19 software. Differences between groups were considered statistically significant at p < 0.05. Results: Twenty-two patients presented multicentric lesions (2.2%). The average age was 43 years. Most of the lesions were bicentric affecting cervix and vagina and cervix and vulva. Only in two cases (9%) there were three sites of genital neoplasia. The authors found four cervical cancer, 17 high grade, and one low grade lesions of the cervix. Eighteen vaginal intraepithelial neoplasia (VAIN), six high grade, 14 low grade, and four vulvar intraepithelial neoplasia (VIN) were found. HPV infection, age > 35 years, multiparity, contraceptive method, immunodeficiency, and level of studies were significantly correlated with multicentric lesions. High percentage of affected margins were found. VIN cases were treated with surgical excision and in two cases microinvasion was found. VAIN III cases were treated with surgical excision or with laser and one case progressed to vaginal cancer. Recurrence after treatment was 27%. Conclusion: Age, multiparity, contraceptive method, immunodeficiency, and level of studies were significantly correlated with multicentric lesion. Multicentric lesions had an increased risk of recurrence and progression to cancer. [ABSTRACT FROM AUTHOR]

We present a theoretical study of scanning tunneling microscopy/microscope (STM) images of two chemisorbed, molecular precursors of O2 and chemisorbed O on Ag(1 1 0). The electronic structure and the equilibrium geometric structure of these precursors were obtained from density functional calculations and STM images were calculated from the Kohn–Sham wave functions using the Tersoff–Hamann approximation. This study provide a quantitative analysis of molecular contrast versus molecular orientation, tip–surface distance and character of tip orbital. Our calculated STM images are in good agreement with experimental STM images. We explain the large separation between the experimentally observed protrusions compared to the O–O bond distance using the vacuum tails of a model wave function for an anti-bonding state of O2. [Copyright &y& Elsevier]

The combination of gas-phase oxygen abundances and stellar metallicities can provide us with unique insights into the metal enrichment histories of galaxies. In this work, we compare the stellar and gas-phase metallicities measured within a 1 Re aperture for a representative sample of 472 star-forming galaxies extracted from the SAMI Galaxy Survey. We confirm that the stellar and interstellar medium (ISM) metallicities are strongly correlated, with scatter ∼3 times smaller than that found in previous works, and that integrated stellar populations are generally more metal-poor than the ISM, especially in low-mass galaxies. The ratio between the two metallicities strongly correlates with several integrated galaxy properties including stellar mass, specific star formation rate, and a gravitational potential proxy. However, we show that these trends are primarily a consequence of: (a) the different star formation and metal enrichment histories of the galaxies, and (b) the fact that while stellar metallicities trace primarily iron enrichment, gas-phase metallicity indicators are calibrated to the enrichment of oxygen in the ISM. Indeed, once both metallicities are converted to the same 'element base' all of our trends become significantly weaker. Interestingly, the ratio of gas to stellar metallicity is always below the value expected for a simple closed-box model, which requires that outflows and inflows play an important role in the enrichment history across our entire stellar mass range. This work highlights the complex interplay between stellar and gas-phase metallicities and shows how care must be taken in comparing them to constrain models of galaxy formation and evolution. [ABSTRACT FROM AUTHOR]

Galaxy internal structure growth has long been accused of inhibiting star formation in disc galaxies. We investigate the potential physical connection between the growth of dispersion-supported stellar structures (e.g. classical bulges) and the position of galaxies on the star-forming main sequence at z ∼ 0. Combining the might of the SAMI and MaNGA galaxy surveys, we measure the λ Re spin parameter for 3289 galaxies over |$9.5 \lt \log M_{\star } [\rm {M}_{\odot }] \lt 12$|⁠. At all stellar masses, galaxies at the locus of the main sequence possess λ Re values indicative of intrinsically flattened discs. However, above |$\log M_{\star }[\rm {M}_{\odot }]\sim 10.5$| where the main sequence starts bending, we find tantalizing evidence for an increase in the number of galaxies with dispersion-supported structures, perhaps suggesting a connection between bulges and the bending of the main sequence. Moving above the main sequence, we see no evidence of any change in the typical spin parameter in galaxies once gravitationally interacting systems are excluded from the sample. Similarly, up to 1 dex below the main sequence, λ Re remains roughly constant and only at very high stellar masses (⁠|$\log M_{\star }[\rm {M}_{\odot }]\gt 11$|⁠), do we see a rapid decrease in λ Re once galaxies decline in star formation activity. If this trend is confirmed, it would be indicative of different quenching mechanisms acting on high- and low-mass galaxies. The results suggest that whilst a population of galaxies possessing some dispersion-supported structure is already present on the star-forming main sequence, further growth would be required after the galaxy has quenched to match the kinematic properties observed in passive galaxies at z ∼ 0. [ABSTRACT FROM AUTHOR]

Recent advances in scanning probe techniques rely on the chemical functionalization of the probe-tip termination by a single molecule. The success of this approach opens the prospect of introducing spin sensitivity through functionalization by a magnetic molecule. We used a nickelocene-terminated tip (Nc-tip), which offered the possibility of producing spin excitations on the tip apex of a scanning tunneling microscope (STM). When the Nc-tip was 100 picometers away from point contact with a surface-supported object, magnetic effects could be probed through changes in the spin excitation spectrum of nickelocene. We used this detection scheme to simultaneously determine the exchange field and the spin polarization of iron atoms and cobalt films on a copper surface with atomic-scale resolution. [ABSTRACT FROM AUTHOR]

We study the balance in dynamical support of 384 galaxies with stellar kinematics out to ≥1.5 R e in the Sydney AAO Multi-object Integral Field (SAMI) Galaxy Survey. We present radial dynamical profiles of the local rotation dominance parameter, V /σ, and local spin, λloc. Although there is a broad range in amplitude, most kinematic profiles monotonically increase across the probed radial range. We do not find many galaxies with kinematic transitions such as those expected between the inner in situ and outer accreted stars within the radial range probed. We compare the V /σ gradient and maximum values to the visual morphologies of the galaxies to better understand the link between visual and kinematic morphologies. We find that the radial distribution of dynamical support in galaxies is linked to their visual morphology. Late-type systems have higher rotational support at all radii and steeper V /σ gradients compared to early-type galaxies. We perform a search for embedded discs, which are rotationally supported discy structures embedded within large scale slowly or non-rotating structures. Visual inspection of the kinematics reveals at most 3 galaxies (out of 384) harbouring embedded discs. This is more than an order of magnitude fewer than the observed fraction in some local studies. Our tests suggest that this tension can be attributed to differences in the sample selection, spatial sampling, and beam smearing due to seeing. [ABSTRACT FROM AUTHOR]

In order to determine the causes of kinematic asymmetry in the Hα gas in the SAMI (Sydney- AAO Multi-object IFS) Galaxy Survey sample, we investigate the comparative influences of environment and intrinsic properties of galaxies on perturbation. We use spatially resolved Hα velocity fields from the SAMI Galaxy Survey to quantify kinematic asymmetry (...) in nearby galaxies and environmental and stellar mass data from the Galaxy And Mass Assembly survey. We find that local environment, measured as distance to nearest neighbour, is inversely correlated with kinematic asymmetry for galaxies with log (M*/M⊙) > 10.0, but there is no significant correlation for galaxies with log (M*/M⊙) < 10.0. Moreover, lowmass galaxies [log (M*/M⊙) < 9.0] have greater kinematic asymmetry at all separations, suggesting a different physical source of asymmetry is important in low-mass galaxies. We propose that secular effects derived from gas fraction and gas mass may be the primary causes of asymmetry in low-mass galaxies. High gas fraction is linked to high σm/V (where σm is Hα velocity dispersion and V the rotation velocity), which is strongly correlated with ..., and galaxies with log (M*/M⊙) < 9.0 have offset ... from the rest of the sample. Further, asymmetry as a fraction of dispersion decreases for galaxies with log (M*/M⊙) < 9.0. Gas mass and asymmetry are also inversely correlated in our sample. We propose that low gas masses in dwarf galaxies may lead to asymmetric distribution of gas clouds, leading to increased relative turbulence. [ABSTRACT FROM AUTHOR]

In the low-redshift Universe (z < 0.3), our view of galaxy evolution is primarily based on fibre optic spectroscopy surveys. Elaborate methods have been developed to address aperture effects when fixed aperture sizes only probe the inner regions for galaxies of ever decreasing redshift or increasing physical size. These aperture corrections rely on assumptions about the physical properties of galaxies. The adequacy of these aperture corrections can be tested with integralfield spectroscopic data. We use integral-field spectra drawn from 1212 galaxies observed as part of the SAMI Galaxy Survey to investigate the validity of two aperture correction methods that attempt to estimate a galaxy's total instantaneous star formation rate.We show that biases arise when assuming that instantaneous star formation is traced by broad-band imaging, and when the aperture correction is built only from spectra of the nuclear region of galaxies. These biases may be significant depending on the selection criteria of a survey sample. Understanding the sensitivities of these aperture corrections is essential for correct handling of systematic errors in galaxy evolution studies. [ABSTRACT FROM AUTHOR]

We report on a reversible structural phase transition of a two-dimensional system that can be locally induced by an external electric field. Two different structural configurations may coexist within a CO monolayer on Cu(111). The balance between the two phases can be shifted by an external electric field, causing the domain boundaries to move, increasing the area of the favored phase controllable both in location and size. If the field is further enhanced new domains nucleate. The arrangement of the CO molecules on the Cu surface is observed in real time and real space with atomic resolution while the electric field driving the phase transition is easily varied over a broad range. Together with the well-known molecular manipulation of CO adlayers, our findings open exciting prospects for combining spontaneous long-range order with man-made CO structures such as "molecule cascades" or "molecular graphene". Our new manipulation mode permits us to bridge the gap between fundamental concepts and the fabrication of arbitrary atomic patterns in large scale, by providing unprecedented insight into the physics of structural phase transitions on the atomic scale. [ABSTRACT FROM AUTHOR]

Purpose of investigation: To document the relationship between smoking and HPV infection, and the risk of developing preinvasive lesions and cervical carcinoma. Materials and Methods: Prospective, cross-sectional descriptive study. A total of 1,007 patients were recruited among women seen at the cervical pathology clinic of Sant Joan de Déu University Hospital in Barcelona (Spain) between January 2003 and March 2011. Patients were asked specifically about their smoking habits. Statistical analyses were done with SPSS v.19 software. Differences between groups were considered statistically significant at p < 0.05. Results: In patients studied, 48.7% were smokers. The average number of cigarettes per day among smoking patients was 7.07 (1-40). In the of patients with HPV infection, 53% were smokers versus 37% of patients without HPV infection (p < 0.05). The average number of cigarettes per day among patients with HPV infection was 7.64 cigarettes/day versus 5.55 cigarettes/day among patients without HPV infection (p < 0.05). In the patients with high-risk HPV genotypes infection, 54.5% were smokers versus 43.2% of patients without high-risk HPV infection (p < 0.05). Risk of HPV infection increases 1.905 times among smoking patients versus no smoking patients (OR = 1.905, CI 95% (1.426 - 2.545), p < 0.05). Among patients with changes associated to HPV and atypical cells, there were 29.2% and 14.4% of smokers, respectively, versus 45.5%, 55.6%, and 48.6% of smokers among patients with grade 1 cervical intraepithelial neoplasia (CIN 1), CIN 2-3, and carcinoma, respectively (p < 0.05). Risk of CIN 2-3 or cervical carcinoma cervical increases 1.642 times among smoking patients versus no smoking ones (OR = 1.642, CI 95% (1.325 - 1.884), p < 0.05). Conclusions: Smoking interferes in the increase of HPV infection prevalence and in an increased risk of CIN and cervical carcinoma. Risk also increases with more cigars smoked per day. [ABSTRACT FROM AUTHOR]

The rates of a hindered molecular rotation induced by tunneling electrons are evaluated using scattering theory within the sudden approximation. Our approach explains the excitation of copper phthalocyanine molecules (CuPc) on Cu(111) as revealed in a recent measurement of telegraph noise in a scanning tunneling microscopy experiment [ Schaffert et al. Nat. Mater. 12 223 (2013)]. A complete explanation of the experimental data is performed by computing the geometry of the adsorbed system, its electronic structure, and the energy transfer between tunneling electrons and the molecule's rotational degree of freedom. The results unambiguously show that tunneling electrons induce a frustrated rotation of the molecule. In addition, the theory determines the spatial distribution of the frustrated rotation excitation, confirming the striking dominance of two out of four molecular lobes in the observed excitation process. This lobe selectivity is attributed to the different hybridizations with the underlying substrate. [ABSTRACT FROM AUTHOR]

We present a systematic investigation of molecule-metal interactions for transition-metal phthalocyanines (TMPc, with TM = Fe, Co, Ni, Cu) adsorbed on Ag( 100). Scanning tunneling spectroscopy and density functional theory provide insight into the charge transfer and hybridization mechanisms of TMPc as a function of increasing occupancy of the 3d metal states. We show that all four TMPc receive approximately one electron from the substrate. Charge transfer occurs from the substrate to the molecules, inducing a charge reorganization in FePc and CoPc, while adding one electron to ligand π Orbitals in NiPc and CuPc. This has opposite consequences on the molecular magnetic moment: In FePc and CoPc the interaction with the substrate tends to reduce the TM spin, whereas, in NiPc and CuPc, an additional spin is induced on the aromatic Pc ligand, leaving the TM spin unperturbed. In CuPc, the presence of both TM and ligand spins leads to a triplet ground state arising from intramolecular exchange coupling between d and π electrons. In FePc and CoPc the magnetic moment of C and N atoms is antiparallel to that of the TM. The different character and symmetry of the frontier orbitals in the TMPc series leads to varying degrees of hybridization and correlation effects, ranging from the mixed-valence (FePc, CoPc) to the Kondo regime (NiPc, CuPc). Coherent coupling between Kondo and inelastic excitations induces finite-bias Kondo resonances involving vibrational transitions in both NiPc and CuPc and triplet-singlet transitions in CuPc. [ABSTRACT FROM AUTHOR]

Abstract: Scanning tunneling microscopy and spectroscopy reveal that the energy of orbitals of individual perylenetetracarboxylic-dianhydride molecules depends on their adsorption geometry. Internal molecular structure appears at characteristic energies for each of the coexisting adsorption domains on Au(788) and Au(111). Tunneling spectroscopy on single molecules belonging to different adsorption domains exhibits an energy shift of the lowest and second-to-lowest unoccupied molecular orbital of ≈0.35eV. On the basis of density functional theory calculations a possible contribution to this shift can be traced back to hydrogen bond-mediated intermolecular interaction. Hence, tunneling spectroscopy can be used as an efficient tool to discriminate between phases of organic molecular layers. [Copyright &y& Elsevier]

We compare the azimuthal distribution of H atoms after scattering off Ag(1 1 0) obtained by molecular dynamics with different H–Ag(1 1 0) potential energy surfaces (PES) and experimental results. We use grazing incident H atoms and low energies (up to 4 keV). Density functional theory (DFT) calculations are performed for the static case of an H atom in front of an Ag(1 1 0) surface. The surface is represented by an 8-atom slab, and the H atoms form 1×1 and 2×2 supercells. The generalized gradient approximation is used. Classical trajectories are evaluated on the obtained PES, and the azimuthal distribution of the scattered atoms is calculated. Good agreement with experiment is obtained which gives us some confidence in the correct description of the system at low energies by the static DFT calculations. These results are also compared with pair-potential calculations. The accuracy of trajectories may be important for the correct evaluation of charge transfer, energy loss and straggling during ion–surface collisions. [Copyright &y& Elsevier]

Loquat fruit growth measured by increases of equatorial diameter adjusts to a logistic curve. By means of sequential measurements of tagged fruits of cultivar ‘Algerie’, curves were obtained that fit significantly to a single sigmoid model in unthinned as well as in heavily thinned trees. Equations defining growth pattern of fruits from thinned and from unthinned trees showed different slopes that reflect greater growth rates under thinning. On the contrary, small and large fruits within the same tree showed minor variations in growth rates, and fruit size at harvest was largely due to fruit size at initial fruit set. Differences in size among fruitlets of the same tree at the time of hand fruit thinning never reversed and led to different commercial categories related with initial size; that allows us to recommend fruit thinning on a size basis. A strong significant correlation was also found at harvest between fresh fruit weight and equatorial diameter. Size and number of seeds were the major determinants of final fruit size in loquat whereas number of leaves and leaf area index of the bearing shoots showed a weak correlation with final size of fruits. [Copyright &y& Elsevier]

An abstract of the article "Feasibility of texture analysis of different regions of the cervix by quantitative ultrasound to evaluate cervical changes along pregnancy," by A. Perez-Moreno and colleagues is presented.

An abstract of the article "Performance of cervical length and cervical consistency index to predict spontaneous preterm birth in low-risk population," by N. Baños and colleagues is presented.