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Chang BY, Shin S, González-Vázquez J, Martín F, Malinovsky VS, Sola IR. Control defeasance by anti-alignment in the excited state. Phys Chem Chem Phys 2019; 21:23620-23625. [PMID: 31624812 DOI: 10.1039/c9cp04427b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We predict anti-alignment dynamics in the excited state of H2+ or related homonuclear dimers in the presence of a strong field. This effect is a general indirect outcome of the strong transition dipole and large polarizabilities typically used to control or to induce alignment in the ground state. In the excited state, however, the polarizabilities have the opposite sign compared to those in the ground state, generating a torque that aligns the molecule perpendicular to the field, deeming any laser-control strategy impossible.
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Engin S, González-Vázquez J, Maliyar GG, Milosavljević AR, Ono T, Nandi S, Iablonskyi D, Kooser K, Bozek JD, Decleva P, Kukk E, Ueda K, Martín F. Full-dimensional theoretical description of vibrationally resolved valence-shell photoionization of H 2O. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2019; 6:054101. [PMID: 31531387 PMCID: PMC6739208 DOI: 10.1063/1.5106431] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
We have performed a full-dimensional theoretical study of vibrationally resolved photoelectron emission from the valence shell of the water molecule by using an extension of the static-exchange density functional theory that accounts for ionization as well as for vibrational motion in the symmetric stretching, antisymmetric stretching, and bending modes. At variance with previous studies performed in centrosymmetric molecules, where vibrationally resolved spectra are mostly dominated by the symmetric stretching mode, in the present case, all three modes contribute to the calculated spectra, including intermode couplings. We have found that diffraction of the ejected electron by the various atomic centers is barely visible in the ratios between vibrationally resolved photoelectron spectra corresponding to different vibrational states of the remaining H2O+ cation (the so-called v-ratios), in contrast to the prominent oscillations observed in K-shell ionization of centrosymmetric molecules, including those that only contain hydrogen atoms around the central atoms, e.g., CH4. To validate the conclusions of our work, we have carried out synchrotron radiation experiments at the SOLEIL synchrotron and determined photoelectron spectra and v-ratios for H2O in a wide range of photon energies, from threshold up to 150 eV. The agreement with the theoretical predictions is good.
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Marggi Poullain S, Klinker M, González-Vázquez J, Martín F. Resonant photoionization of O 2 up to the fourth ionization threshold. Phys Chem Chem Phys 2019; 21:16497-16504. [PMID: 31322631 DOI: 10.1039/c9cp02150g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We present a detailed theoretical study of valence-shell photoionization of the oxygen molecule by using the recently proposed XCHEM method. This method makes use of a hybrid Gaussian and B-spline basis in the framework of a close-coupling approach to describe electron correlation in the molecular electronic continuum at a level comparable to that provided by multi-reference configuration interaction methods in bound state calculations. The computed total and partial photoionization cross sections are presented and discussed, with emphasis on the series of autoionizing resonances that appear between the first and the fourth ionization thresholds, i.e., photon energies between 12 and 18 eV. More than fifty autoionizing states are identified, including series not previously reported in the literature, and their energy positions and widths are provided. The present results illustrate the potential of the XCHEM approach to accurately describe molecular autoionization, which is mostly due to electron correlation. This is relevant in view of current experimental efforts aimed at providing real-time (attosecond) imaging of autoionization dynamics in molecules.
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Alonso R, Cedena MT, Gómez‐Grande A, Ríos R, Moraleda JM, Cabañas V, Moreno MJ, López‐Jiménez J, Martín F, Sanz A, Valeri A, Jiménez A, Sánchez R, Lahuerta JJ, Martínez‐López J. Imaging and bone marrow assessments improve minimal residual disease prediction in multiple myeloma. Am J Hematol 2019; 94:853-861. [PMID: 31074033 DOI: 10.1002/ajh.25507] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 01/01/2023]
Abstract
The value of minimal residual disease (MRD) status by bone marrow and imaging analysis as independent prognostic factors has been well established in multiple myeloma (MM). Nevertheless data about their potential complementarity for a more accurate assessment are limited. With this aim, we retrospectively analyzed the prediction of outcome with the combination of PET-CT and MRD, assessed by multiparameter flow cytometry (MFC) in 103 patients with newly diagnosed MM. We confirmed the benefit in terms of progression-free survival (PFS), linked to the achievement of negativity by MFC (hazard ratio [HR] 0.53; 95% confidence interval [CI]: 0.28-0.98), and PET-CT (HR 0.18; 95% CI: 0.09-0.36) individually. By combining both techniques, patients who became MRD-/PET-, with a median of PFS 92 months, had significant prolonged median PFS (P < .001). This is compared with MRD+/PET- and PET+ patients (median PFS of 45 and 28 months, respectively). We observed a significant difference (P = .003) in overall survival (OS) outcomes between MRD-/PET- and MRD+/PET- patients (4-year OS 94.2% and 100%, respectively), vs PET+ patients (4-year OS 73.8%). All survival results were confirmed in a conditional landmark analysis. These findings support the potential complementarity between PET-CT and MFC, and highlight their better predictive capability when improving sensitivity.
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Palacios A, Martín F. The quantum chemistry of attosecond molecular science. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2019. [DOI: 10.1002/wcms.1430] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Del Cueto M, Muzas AS, Frankcombe TJ, Martín F, Díaz C. Prominent out-of-plane diffraction in helium scattering from a methyl-terminated Si(111) surface. Phys Chem Chem Phys 2019; 21:15879-15887. [PMID: 31286123 DOI: 10.1039/c9cp02141h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Due to their electrochemical and oxidative stability, organic-terminated semiconductor surfaces are well suited to applications in, for example, photoelectrodes and electrochemical cells, which explains the lively interest in their detailed characterization. Helium atom scattering (HAS) is a useful tool to carry out such characterization. Here, we have simulated HAS in He/CH3-Si(111) based on density functional theory (DFT) potential energy surfaces (PESs) and multi-configuration time-dependent Hartree (MCTDH) dynamics. Our analysis of HAS shows that most diffraction taking place in this system corresponds to high-order out-of-plane peaks. This is a general trend that does not depend on the specific features of the simulations, such as the inclusion or not of the van der Waals long-range effects. This is the first and only He-surface system for which such huge out-of-plane diffraction has been described. This striking theoretical finding should encourage new experimental developments to confirm this previously unreported effect.
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Barreau L, Petersson CLM, Klinker M, Camper A, Marante C, Gorman T, Kiesewetter D, Argenti L, Agostini P, González-Vázquez J, Salières P, DiMauro LF, Martín F. Disentangling Spectral Phases of Interfering Autoionizing States from Attosecond Interferometric Measurements. PHYSICAL REVIEW LETTERS 2019; 122:253203. [PMID: 31347882 DOI: 10.1103/physrevlett.122.253203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/15/2019] [Indexed: 06/10/2023]
Abstract
We have determined spectral phases of Ne autoionizing states from extreme ultraviolet and midinfrared attosecond interferometric measurements and ab initio full-electron time-dependent theoretical calculations in an energy interval where several of these states are coherently populated. The retrieved phases exhibit a complex behavior as a function of photon energy, which is the consequence of the interference between paths involving various resonances. In spite of this complexity, we show that phases for individual resonances can still be obtained from experiment by using an extension of the Fano model of atomic resonances. As simultaneous excitation of several resonances is a common scenario in many-electron systems, the present work paves the way to reconstruct electron wave packets coherently generated by attosecond pulses in systems larger than helium.
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Kling NG, Díaz-Tendero S, Obaid R, Disla MR, Xiong H, Sundberg M, Khosravi SD, Davino M, Drach P, Carroll AM, Osipov T, Martín F, Berrah N. Time-resolved molecular dynamics of single and double hydrogen migration in ethanol. Nat Commun 2019; 10:2813. [PMID: 31249306 PMCID: PMC6597707 DOI: 10.1038/s41467-019-10571-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 04/30/2019] [Indexed: 11/17/2022] Open
Abstract
Being the lightest, most mobile atom that exists, hydrogen plays an important role in the chemistry of hydrocarbons, proteins and peptides and most biomolecules. Hydrogen can undergo transfer, exchange and migration processes, having considerable impact on the chemical behavior of these molecules. Although much has been learned about reaction dynamics involving one hydrogen atom, less is known about those processes where two or more hydrogen atoms participate. Here we show that single and double hydrogen migrations occurring in ethanol cations and dications take place within a few hundred fs to ps, using a 3D imaging and laser pump-probe technique. For double hydrogen migration, the hydrogens are not correlated, with the second hydrogen migration promoting the breakup of the C-O bond. The probability of double hydrogen migration is quite significant, suggesting that double hydrogen migration plays a more important role than generally assumed. The conclusions are supported by state-of-the-art molecular dynamics calculations.
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Trabattoni A, Galli M, Lara-Astiaso M, Palacios A, Greenwood J, Tavernelli I, Decleva P, Nisoli M, Martín F, Calegari F. Charge migration in photo-ionized aromatic amino acids. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20170472. [PMID: 30929627 PMCID: PMC6452047 DOI: 10.1098/rsta.2017.0472] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Attosecond pump-probe spectroscopy is a unique tool for the direct observation of the light-activated electronic motion in molecules and it offers the possibility to capture the first instants of a chemical reaction. Recently, advances in attosecond technology allowed the charge migration processes to be revealed in biochemically relevant molecules. Although this purely electronic process might be key for a future chemistry at the electron time scale, the influence of this ultrafast charge flow on the reactivity of a molecule is still debated. In this work, we exploit extreme ultraviolet attosecond pulses to activate charge migration in two aromatic amino acids, namely phenylalanine and tryptophan. Advanced numerical calculations are performed to interpret the experimental data and to discuss the effects of the nuclear dynamics on the activated quantum coherences. By comparing the experimental results obtained in the two molecules, we show that the presence of different functional groups strongly affects the fragmentation pathways, as well as the charge rearrangement. The observed charge dynamics indeed present peculiar aspects, including characteristic periodicities and decoherence times. Numerical results indicate that, even for a very large molecule such as tryptophan, the quantum coherences can survive the nuclear dynamics for several femtoseconds. These results open new and important perspectives for a deeper understanding of the photo-induced charge dynamics, as a promising tool to control the reactivity of bio-relevant molecules via photo-excitation. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
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Aguirre NF, Díaz-Tendero S, IdBarkach T, Chabot M, Béroff K, Alcamí M, Martín F. Fully versus constrained statistical fragmentation of carbon clusters and their heteronuclear derivatives. J Chem Phys 2019; 150:144301. [PMID: 30981259 DOI: 10.1063/1.5083864] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Microcanonical Metropolis Monte Carlo (MMMC) method has been shown to describe reasonably well fragmentation of clusters composed of identical atomic species. However, this is not so clear in the case of heteronuclear clusters as some regions of phase space might be inaccessible due to the different mobility of the different atomic species, the existence of large isomerization barriers, or the quite different chemical nature of the possible intermediate species. In this paper, we introduce a constrained statistical model that extends the range of applicability of the MMMC method to such mixed clusters. The method is applied to describe fragmentation of isolated clusters with high, moderate, and no heteronuclear character, namely, CnHm, CnN, and Cn clusters for which experimental fragmentation branching ratios are available in the literature. We show that the constrained statistical model describes fairly well fragmentation of CnHm clusters in contrast with the poor description provided by the fully statistical model. The latter model, however, works pretty well for both Cn and CnN clusters, thus showing that the ultimate reason for this discrepancy is the inability of the MMMC method to selectively explore the whole phase space. This conclusion has driven us to predict the fragmentation patterns of the C4N cluster for which experiments are not yet available.
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Del Cueto M, Maurer RJ, Al Taleb A, Farías D, Martín F, Díaz C. Performance of van der Waals DFT approaches for helium diffraction on metal surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:135901. [PMID: 30625425 DOI: 10.1088/1361-648x/aafcfd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The ability of the different approaches proposed to date to include the effects of van der Waals (vdW) dispersion forces in density functional theory (DFT) is currently under debate. Here, we used the diffraction of He on a Ru(0 0 0 1) surface as a challenging benchmark system to analyze the suitability of several representative approaches, from the ones correcting the exchange-correlation generalized gradient approximation (GGA) functional, to the ones correcting the DFT energies through pairwise-based methods. To perform our analysis, we have built seven continuous potential energy surfaces (PESs) and carried out quantum dynamics simulations using a multi-configuration time-dependent Hartree method. Our analysis reveals that standard DFT within the PBE-GGA framework, although it overestimates diffraction probabilities, yields the best results in comparison with available experimental measurements. On the other hand, although several of the existing vdW DFT approaches yield physisorption wells in very good agreement with experiment, they all seem to overestimate the long-distance corrugation of the PES, the region probed by He scattering, resulting in a large overestimation of diffraction probabilities.
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Rivas E, Santiago JL, Lechón Y, Martín F, Ariño A, Pons JJ, Santamaría JM. CFD modelling of air quality in Pamplona City (Spain): Assessment, stations spatial representativeness and health impacts valuation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 649:1362-1380. [PMID: 30308906 DOI: 10.1016/j.scitotenv.2018.08.315] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/20/2018] [Accepted: 08/23/2018] [Indexed: 06/08/2023]
Abstract
A methodology based on CFD-RANS simulations (WA CFD-RANS, Weighted Averaged Computational Fluid Dynamic-Reynolds-Averaged Navier-Stokes simulations) which includes appropriate modifications, has been applied to compute the annual, seasonal, and hourly average concentration of NO2 and NOX throughout the city of Pamplona (Spain) at pedestrian level during 2016. The results have been evaluated using measurements provided both by the city's network of air quality monitoring stations and by a network of mobile microsensors carried around by cyclists during their daily commutes, obtaining a maximum relative error lower than 30% when computing NO2 annual average concentrations. The model has taken into account the actual city layout in three dimensions, as well as the traffic emissions. The resulting air pollution maps provided information critical for studying the traffic-related health effects of NO2 and their associated external costs in the city of Pamplona and the spatial representativeness of the current network of air quality monitoring stations (it has not been carried out for an entire city to date). The developed methodology can be applied to similar cities, providing useful information for the decision-makers.
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Plésiat E, Canton SE, Bozek JD, Decleva P, Martín F. Resonant Photoelectron Confinement in the SF6 Molecule. J Phys Chem A 2019; 123:1062-1068. [DOI: 10.1021/acs.jpca.8b12237] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Oberli S, González-Vázquez J, Rodríguez-Perelló E, Sodupe M, Martín F, Picón A. Site-selective-induced isomerization of formamide. Phys Chem Chem Phys 2019; 21:25626-25634. [DOI: 10.1039/c9cp04441h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We theoretically demonstrate the possibility to site-selectively induce and track isomerization in formamide by using a femtosecond X-ray-pump/X-ray-probe scheme.
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Wang Y, Díaz-Tendero S, Alcamí M, Martín F. Aromaticity, Coulomb repulsion, π delocalization or strain: who is who in endohedral metallofullerene stability? Phys Chem Chem Phys 2019; 21:124-131. [DOI: 10.1039/c8cp06707d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Three different models for endohedral metallofullerene structure prediction are compared, revealing the physical origin of the stability of these compounds.
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Richter M, González-Vázquez J, Mašín Z, Brambila DS, Harvey AG, Morales F, Martín F. Ultrafast imaging of laser-controlled non-adiabatic dynamics in NO2 from time-resolved photoelectron emission. Phys Chem Chem Phys 2019; 21:10038-10051. [PMID: 31046039 DOI: 10.1039/c9cp00649d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Imaging and controlling the ultrafast conical intersection dynamics in NO2 using the latest advances in attosecond and light-synthesizer technology.
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Gómez E, Martín F, Nogacka AM, Salazar N, Aláez L, Alcorta E, Gueimonde M, De Los Reyes-Gavilán CG. Impact of probiotics on development and behaviour in Drosophila melanogaster - a potential in vivo model to assess probiotics. Benef Microbes 2018; 10:179-188. [PMID: 30574803 DOI: 10.3920/bm2018.0012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In vitro models are frequently used in probiotic research. However, such models often fail to predict in vivo functionality and efficacy. This fact complicates the screening process for selecting the most suitable strains, prior to accomplish expensive animal studies and clinical intervention trials. Therefore, additional sensitive, discriminating and cost-effective models are needed to conduct preliminary assays before undertaking human intervention studies definitely proving efficacy. With this purpose in mind, we explored the potential of axenic Drosophila melanogaster populations as well as of these axenic flies treated with probiotic microbial strains as a model to test the effects of probiotics on a subset of developmental and behavioural traits. An axenic D. melanogaster progeny from the wild-type Canton S strain was obtained and its eggs were further developed until pupae eclosion occurred in growth medium containing either of two probiotic strains: Bifidobacterium animalis subsp. lactis Bb12 or Lactobacillus rhamnosus GG. Whereas B. animalis Bb12 colonised the flies, the capacity of L. rhamnosus LGG to colonise was considerably lower in our experimental conditions. Regarding the influence of microbial load on the flies' development, the axenic condition caused a decrease in egg survival, and lowered adults' average weight with respect to wild-type flies. Both probiotics were able to counteract these effects. An earlier emergence of adults was observed from eggs treated with L. rhamnosus GG in comparison to the other fly populations. The axenic condition did not influence negative geotaxis behaviour in Drosophila; however, flies mono-associated with B. animalis Bb12 moved faster than wild-type. Our results suggest that the use of axenic/probiotic-treated D. melanogaster populations may be an affordable model for preliminary testing of the effects of probiotics on developmental or behavioural aspects.
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Navarro JJ, Pisarra M, Nieto-Ortega B, Villalva J, Ayani CG, Díaz C, Calleja F, Miranda R, Martín F, Pérez EM, Vázquez de Parga AL. Graphene catalyzes the reversible formation of a C-C bond between two molecules. SCIENCE ADVANCES 2018; 4:eaau9366. [PMID: 30555920 PMCID: PMC6294602 DOI: 10.1126/sciadv.aau9366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C-C bond between -CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is multifaceted: First, it allows for an efficient charge transfer between the surface and the reactants, thus favoring changes in carbon hybridization; second, it holds the reactants in place and makes them reactive. The reaction is fully reversible by injecting electrons with an STM tip on the empty molecular orbitals of the product. The making and breaking of the C-C bond is accompanied by the switching off and on of a Kondo resonance, so that the system can be viewed as a reversible magnetic switch controlled by a chemical reaction.
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Villoslada Á, Rivera C, Escudero N, Martín F, Blanco D, Moreno L. Hand Exo-Muscular System for Assisting Astronauts During Extravehicular Activities. Soft Robot 2018; 6:21-37. [PMID: 30457930 DOI: 10.1089/soro.2018.0020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human exploration of the Solar System is one of the most challenging objectives included in the space programs of the most important space agencies in the world. Since the Apollo program, and especially with the construction and operation of the International Space Station, extravehicular activities (EVA) have become an important part of space exploration. This article presents a soft hand exoskeleton designed to address one of the problems that astronauts face during spacewalks: hand fatigue caused by the pressurized EVA gloves. This device will reduce the stiffness of the spacesuit glove by counteracting the force exerted by the pressurized glove. To this end, the system makes use of a set of six flexible actuators, which use a shape memory alloy (SMA) wire as the actuating element. SMAs have been chosen because some of their features, such as low volume and high force-to-weight ratio, make them a suitable choice taking into account the constraints imposed by the use of the device in a spacesuit. Besides describing the different mechanical and electronic subsystems that compose the exoskeleton, this article presents a preliminary assessment of the device; several tests to characterize its nominal operation have been carried out, as well as position and force control tests to study its controllability and evaluate its suitability as a force assistive device.
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Borge R, Santiago JL, de la Paz D, Martín F, Domingo J, Valdés C, Sánchez B, Rivas E, Rozas MT, Lázaro S, Pérez J, Fernández Á. Corrigendum to "Application of a short term air quality action plan in Madrid (Spain) under a high-pollution episode - Part II: Assessment from multi-scale modelling" [Sci. Total Environ. 635C (2018) 1575-1585]. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 637-638:1627. [PMID: 29807663 DOI: 10.1016/j.scitotenv.2018.05.202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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Holzmeier F, Bello RY, Hervé M, Achner A, Baumann TM, Meyer M, Finetti P, Di Fraia M, Gauthier D, Roussel E, Plekan O, Richter R, Prince KC, Callegari C, Bachau H, Palacios A, Martín F, Dowek D. Control of H_{2} Dissociative Ionization in the Nonlinear Regime Using Vacuum Ultraviolet Free-Electron Laser Pulses. PHYSICAL REVIEW LETTERS 2018; 121:103002. [PMID: 30240272 DOI: 10.1103/physrevlett.121.103002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 06/08/2023]
Abstract
The role of the nuclear degrees of freedom in nonlinear two-photon single ionization of H_{2} molecules interacting with short and intense vacuum ultraviolet pulses is investigated, both experimentally and theoretically, by selecting single resonant vibronic intermediate neutral states. This high selectivity relies on the narrow bandwidth and tunability of the pulses generated at the FERMI free-electron laser. A sustained enhancement of dissociative ionization, which even exceeds nondissociative ionization, is observed and controlled as one selects progressively higher vibronic states. With the help of ab initio calculations for increasing pulse durations, the photoelectron and ion energy spectra obtained with velocity map imaging allow us to identify new photoionization pathways. With pulses of the order of 100 fs, the experiment probes a timescale that lies between that of ultrafast dynamical processes and that of steady state excitations.
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Borge R, Santiago JL, de la Paz D, Martín F, Domingo J, Valdés C, Sánchez B, Rivas E, Rozas MT, Lázaro S, Pérez J, Fernández Á. Application of a short term air quality action plan in Madrid (Spain) under a high-pollution episode - Part II: Assessment from multi-scale modelling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 635:1574-1584. [PMID: 29739658 DOI: 10.1016/j.scitotenv.2018.04.323] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/12/2018] [Accepted: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Air pollution continues to be one of the main issues in urban areas. In addition to air quality plans and emission abatement policies, additional measures for high pollution episodes are needed to avoid exceedances of hourly limit values under unfavourable meteorological conditions such as the Madrid's short-term action NO2 protocol. In December 2016 there was a strong atmospheric stability episode that turned out in generalized high NO2 levels, causing the stage 3 of the NO2 protocol to be triggered for the first time in Madrid (29th December). In addition to other traffic-related measures, this involves access restrictions to the city centre (50% to private cars). We simulated the episode with and without measures under a multi-scale modelling approach. A 1 km2 resolution modelling system based on WRF-SMOKE-CMAQ was applied to assess city-wide effects while the Star-CCM+ (RANS CFD model) was used to investigate the effect at street level in a microscale domain in the city centre, focusing on Gran Vía Avenue. Changes in road traffic were simulated with the mesoscale VISUM model, incorporating real flux measurements during those days. The corresponding simulations suggest that the application of the protocol during this particular episode may have prevented concentrations to increase by 24 μg·m-3 (14% respect to the hypothetical no action scenario) downtown although it may have cause NO2 to slightly increase in the city outskirts due to traffic redistribution. Speed limitation and parking restrictions alone (stages 1 and 2 respectively) have a very limited effect. The microscale simulation provides consistent results but shows an important variability at street level, with reduction above 100 μg·m-3 in some spots inside Gran Vía. Although further research is needed, these results point out the need to implement short-term action plans and to apply a consistent multi-scale modelling assessment to optimize urban air quality abatement strategies.
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Lara-Astiaso M, Galli M, Trabattoni A, Palacios A, Ayuso D, Frassetto F, Poletto L, De Camillis S, Greenwood J, Decleva P, Tavernelli I, Calegari F, Nisoli M, Martín F. Attosecond Pump-Probe Spectroscopy of Charge Dynamics in Tryptophan. J Phys Chem Lett 2018; 9:4570-4577. [PMID: 30044916 DOI: 10.1021/acs.jpclett.8b01786] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Attosecond pump-probe experiments performed in small molecules have allowed tracking charge dynamics in the natural time scale of electron motion. That this is also possible in biologically relevant molecules is still a matter of debate, because the large number of available nuclear degrees of freedom might destroy the coherent charge dynamics induced by the attosecond pulse. Here we investigate extreme ultraviolet-induced charge dynamics in the amino acid tryptophan. We find that, although nuclear motion and nonadiabatic effects introduce some decoherence in the moving electron wave packet, these do not significantly modify the coherence induced by the attosecond pulse during the early stages of the dynamics, at least for molecules in their equilibrium geometry. Our conclusions are based on elaborate theoretical calculations and the experimental observation of sub-4 fs dynamics, which can only be reasonably assigned to electronic motion. Hence, attosecond pump-probe spectroscopy appears as a promising approach to induce and image charge dynamics in complex molecules.
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Plésiat E, Lara-Astiaso M, Decleva P, Palacios A, Martín F. Real-Time Imaging of Ultrafast Charge Dynamics in Tetrafluoromethane from Attosecond Pump-Probe Photoelectron Spectroscopy. Chemistry 2018; 24:12061-12070. [PMID: 29995986 DOI: 10.1002/chem.201802788] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/28/2018] [Indexed: 11/09/2022]
Abstract
A pump-probe experiment in the tetrafluoro-methane (CF4 ) molecule has been theoretically simulated, allowing one to access electron dynamics in its natural time scale: the attosecond. The chosen pump and probe pulses can be currently produced in most attosecond laboratories. In this scheme, CF4 is first ionized by an extreme UV (XUV) attosecond pulse and the charge dynamics induced in the corresponding cation is probed with a few-femtosecond visible light (VIS) pulse. We demonstrate that modulations in the calculated photoelectron spectra with the pump-probe delay reflect the dynamics of the XUV-induced electronic wave packet. In particular, from the analysis of these modulations in the interval of time delays where the pump and probe pulses do not overlap any more, one has access to the amplitudes and phases of the different components of the electronic wave packet generated by the attosecond pulse. These reflect a complex dynamics that basically consists of very fast charge fluctuations occurring all over the molecule without any preference for a particular molecular site.
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