Examinando por Autor "Sobrado, J. M."

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A chamber for studying planetary environments and its applications to astrobiology
(IOP Science Publishing, 2006-07-13) Mateo Martí, Eva; Prieto Ballesteros, O.; Sobrado, J. M.; Gómez Elvira, J.; Martín Gago, J. A.; Instituto Nacional de Técnica Aeroespacial (INTA); Comunidad de Madrid
We have built a versatile environmental simulation chamber capable of reproducing atmospheric compositions and surface temperatures for most of the planetary objects. It has been especially developed to make feasible in situ irradiation and characterization of the sample under study. The total pressure in the chamber can range from 5 to 5 × 10−9 mbar. The required atmospheric composition is regulated via a residual gas analyser with ca ppm precision. Temperatures can be set from 4 K to 325 K. The sample under study can be irradiated with ion and electron sources, a deuterium ultraviolet (UV) lamp and a noble-gas discharge UV lamp. One of the main technological challenges of this device is to provide the user the possibility of performing ion and electron irradiation at a total pressure of 0.5 mbar. This is attained by means of an efficient differential pumping system. The in situ analysis techniques implemented are UV spectroscopy and infrared spectroscopy (IR). This machine is especially suitable for following the chemical changes induced in a particular sample by irradiation in a controlled environment. Therefore, it can be used in different disciplines such as planetary geology, astrobiology, environmental chemistry, materials science and for instrumentation testing.
Acceso Abierto
Broad-band high-resolution rotational spectroscopy for laboratory astrophysics
(EDP Science, 2019-06-07) Cernicharo, J.; Gallego, J. D.; López Pérez, Jose A.; Tercero, Felix; Tanarro, I.; Beltrán, F.; De Vicente, P.; Lauwaet, K.; Alemán, Belén; Moreno, E.; Herrero, V. J.; Doménech, Jose Luis; Ramírez, S. I.; Bermúdez, Celina; Peláez, R. J.; Patino Esteban, Marina; López Fernández, Isaac; García Álvaro, Sonia; García Carreño, Pablo; Cabezas, Carlos; Malo, Inmaculada; Amils, R.; Sobrado, J. M.; Díez González, C.; Hernandéz, Jose M.; Tercero, B.; Santoro, G.; Martínez, L.; Castellanos, Marcelo; Vaquero Jiménez, B.; Pardo, Juan R.; Barbas, L.; López Fernández, Jose Antonio; Aja, B.; Leuther, A.; Martín-Gago, J. A.; Instituto Nacional de Técnica Aeroespacial (INTA); European Commission (EC); Agencia Estatal de Investigación (AEI)
We present a new experimental set-up devoted to the study of gas phase molecules and processes using broad-band high spectral resolution rotational spectroscopy. A reactor chamber is equipped with radio receivers similar to those used by radio astronomers to search for molecular emission in space. The whole range of the Q (31.5–50 GHz) and W bands (72–116.5 GHz) is available for rotational spectroscopy observations. The receivers are equipped with 16 × 2.5 GHz fast Fourier transform spectrometers with a spectral resolution of 38.14 kHz allowing the simultaneous observation of the complete Q band and one-third of the W band. The whole W band can be observed in three settings in which the Q band is always observed. Species such as CH3CN, OCS, and SO2 are detected, together with many of their isotopologues and vibrationally excited states, in very short observing times. The system permits automatic overnight observations, and integration times as long as 2.4 × 105 s have been reached. The chamber is equipped with a radiofrequency source to produce cold plasmas, and with four ultraviolet lamps to study photochemical processes. Plasmas of CH4, N2, CH3CN, NH3, O2, and H2, among other species, have been generated and the molecular products easily identified by the rotational spectrum, and via mass spectrometry and optical spectroscopy. Finally, the rotational spectrum of the lowest energy conformer of CH3CH2NHCHO (N-ethylformamide), a molecule previously characterized in microwave rotational spectroscopy, has been measured up to 116.5 GHz, allowing the accurate determination of its rotational and distortion constants and its search in space.
Restringido
INFRA-ICE: An ultra-high vacuum experimental station for laboratory astrochemistry
(American Institute of Physics, 2020-12-02) Santoro, G.; Sobrado, J. M.; Tajuelo Castilla, G.; Accolla, M.; Martínez, L.; Azpeitia, J.; Lauwaet, K.; Cernicharo, J.; Ellis, G. J.; Martín Gago, J. A.; European Commission (EC); Spanish Research Agency (AEI); Comunidad de Madrid; Castilla, G. [0000-0001-7877-2543]; Cernicharo, J. [0000-0002-3518-2524]; Martín Gago, J. A. [0000-0003-2663-491X]; Santoro, G. [0000-0003-4751-2209]; Martínez Orellana, L. [0000-0002-9370-2962]; Sobrado, J. M. [0000-0002-7359-0262]; Ellis, G. [0000-0003-4851-6092]
Laboratory astrochemistry aims at simulating, in the laboratory, some of the chemical and physical processes that operate in different regions of the universe. Amongst the diverse astrochemical problems that can be addressed in the laboratory, the evolution of cosmic dust grains in different regions of the interstellar medium (ISM) and its role in the formation of new chemical species through catalytic processes present significant interest. In particular, the dark clouds of the ISM dust grains are coated by icy mantles and it is thought that the ice-dust interaction plays a crucial role in the development of the chemical complexity observed in space. Here, we present a new ultra-high vacuum experimental station devoted to simulating the complex conditions of the coldest regions of the ISM. The INFRA-ICE machine can be operated as a standing alone setup or incorporated in a larger experimental station called Stardust, which is dedicated to simulate the formation of cosmic dust in evolved stars. As such, INFRA-ICE expands the capabilities of Stardust allowing the simulation of the complete journey of cosmic dust in space, from its formation in asymptotic giant branch stars to its processing and interaction with icy mantles in molecular clouds. To demonstrate some of the capabilities of INFRA-ICE, we present selected results on the ultraviolet photochemistry of undecane (C11H24) at 14 K. Aliphatics are part of the carbonaceous cosmic dust, and recently, aliphatics and short n-alkanes have been detected in situ in the comet 67P/Churyumov-Gerasimenko.
Restringido
Interplay between Fast Diffusion and Molecular Interaction in the Formation of Self-Assembled Nanostructures of S-Cysteine on Au(111)
(ACS Publications, 2010-01-21) Mateo Martí, Eva; Rogero, Celia; González, César; Sobrado, J. M.; De Andrés, Pedro L.; Martín Gago, J. A.
We have studied the first stages leading to the formation of self-assembled monolayers of S-cysteine molecules adsorbed on a Au(111) surface. Density functional theory (DFT) calculations for the adsorption of individual cysteine molecules on Au(111) at room temperature show low-energy barriers all over the 2D Au(111) unit cell. As a consequence, cysteine molecules diffuse freely on the Au(111) surface and they can be regarded as a 2D molecular gas. The balance between molecule−molecule and molecule−substrate interactions induces molecular condensation and evaporation from the morphological surface structures (steps, reconstruction edges, etc.) as revealed by scanning tunnelling microscopy (STM) images. These processes lead progressively to the formation of a number of stable arrangements, not previously reported, such as single-molecular rows, trimers, and 2D islands. The condensation of these structures is driven by the aggregation of new molecules, stabilized by the formation of electrostatic interactions between adjacent NH3+ and COO− groups, together with adsorption at a slightly more favorable quasi-top site of the herringbone Au reconstruction.
Restringido
Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars exploration
(AIP Publishing, 2014-03-25) Sobrado, J. M.; Martín Soler, J.; Martín Gago, J. A.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO)
We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10−6 mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.
Acceso Abierto
Mimicking the Martian Hydrological Cycle: A Set-Up to Introduce Liquid Water in Vacuum
(Multidisciplinary Digital Publishing Institute (MDPI), 2020-10-29) Sobrado, J. M.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI)
Liquid water is well known as the life ingredient as a solvent. However, so far, it has only been found in liquid state on this planetary surface. The aim of this experiment and technological development was to test if a moss sample is capable of surviving in Martian conditions. We built a system that simulates the environmental conditions of the red planet including its hydrological cycle. This laboratory facility enables us to control the water cycle in its three phases through temperature, relative humidity, hydration, and pressure with a system that injects water droplets into a vacuum chamber. We successfully simulated the daytime and nighttime of Mars by recreating water condensation and created a layer of superficial ice that protects the sample against external radiation and minimizes the loss of humidity due to evaporation to maintain a moss sample in survival conditions in this extreme environment. We performed the simulations with the design and development of different tools that recreate Martian weather in the MARTE simulation chamber.
Acceso Abierto
New results on thermal and photodesorption of CO ice using the novel InterStellar Astrochemistry Chamber (ISAC)
(EDP Science, 2010-11-09) Muñoz Caro, G. M.; Jiménez Escobar, A.; Martín Gago, J. A.; Rogero, Celia; Atienza, C.; Puertas, S.; Sobrado, J. M.; Torres Redondo, J.; Ministerio de Ciencia e Innovación (MICINN); Instituto Nacional de Técnica Aeroespacial (INTA)
Aims. We present the novel InterStellar Astrochemistry Chamber (ISAC), designed for studying solids (ice mantles, organics, and silicates) in interstellar and circumstellar environments: characterizing their physico-chemical properties and monitoring their evolution as caused by (i) vacuum-UV irradiation; (ii) cosmic ray irradiation; and (iii) thermal processing. Experimental study of thermal and photodesorption of the CO ice reported here simulates the freeze-out and desorption of CO on grains, providing new information on these processes. Methods. ISAC is an UHV set-up, with base pressure down to P = 2.5 × 10-11 mbar, where an ice layer is deposited at 7 K and can be UV-irradiated. The evolution of the solid sample was monitored by in situ transmittance FTIR spectroscopy, while the volatile species were monitored by QMS. Results. The UHV conditions of ISAC allow experiments under extremely clean conditions. Transmittance FTIR spectroscopy coupled to QMS proved to be ideal for in situ monitoring of ice processes that include radiation and thermal annealing. Thermal desorption of CO starting at 15 K, induced by the release of H2 from the CO ice, was observed. We measured the photodesorption yield of CO ice per incident photon at 7, 8, and 15 K, respectively yielding 6.4 ± 0.5 × 10-2, 5.4 ± 0.5 × 10-2, and 3.5 ± 0.5 × 10-2 CO molecules photon (7.3–10.5 eV)-1. Our value of the photodesorption yield of CO ice at 15 K is about one order of magnitude higher than the previous estimate. We confirmed that the photodesorption yield is constant during irradiation and independent of the ice thickness. Only below ~ 5 monolayers ice thickness the photodesorption rate decreases, which suggests that only the UV photons absorbed in the top 5 monolayers led to photodesorption. The measured CO photodesorption quantum yield at 7 K per absorbed photon in the top 5 monolayers is 3.4 molecules photon-1. Conclusions. Experimental values were used as input for a simple model of a quiescent cloud interior. Photodesorption seems to explain the observations of CO in the gas phase for densities below 3–7 × 104 cm-3. For the same density of a cloud, 3 × 104 cm-3, thermal desorption of CO is not triggered until T = 14.5 K. This has important implications for CO ice mantle build up in dark clouds.
Acceso Abierto
Precisely controlled fabrication, manipulation and in-situ analysis of Cu based nanoparticles
(Nature, 2018-05-08) Martínez, Lidia; Lauwaet, K.; Santoro, G.; Sobrado, J. M.; Peláez, R. J.; Herrero, V. J.; Tanarro, I.; Ellis, G. J.; Cernicharo, J.; Joblin, C.; Huttel, Y.; Martín-Gago, J. A.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO); European Commission (EC); Agencia Estatal de Investigación (AEI)
The increasing demand for nanostructured materials is mainly motivated by their key role in a wide variety of technologically relevant fields such as biomedicine, green sustainable energy or catalysis. We have succeeded to scale-up a type of gas aggregation source, called a multiple ion cluster source, for the generation of complex, ultra-pure nanoparticles made of different materials. The high production rates achieved (tens of g/day) for this kind of gas aggregation sources, and the inherent ability to control the structure of the nanoparticles in a controlled environment, make this equipment appealing for industrial purposes, a highly coveted aspect since the introduction of this type of sources. Furthermore, our innovative UHV experimental station also includes in-flight manipulation and processing capabilities by annealing, acceleration, or interaction with background gases along with in-situ characterization of the clusters and nanoparticles fabricated. As an example to demonstrate some of the capabilities of this new equipment, herein we present the fabrication of copper nanoparticles and their processing, including the controlled oxidation (from Cu0 to CuO through Cu2O, and their mixtures) at different stages in the machine.
Restringido
Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes
(Nature, 2019-10-21) Martínez, Lidia; Santoro, G.; Merino, P.; Accolla, M.; Lauwaet, K.; Sobrado, J. M.; Sabbah, H.; Peláez, R. J.; Herrero, V. J.; Tanarro, I.; Agúndez, Marcelino; Martín Jiménez, Alberto; Otero, Roberto; Ellis, G. J.; Joblin, C.; Cernicharo, J.; Martín-Gago, J. A.; Instituto Nacional de Técnica Aeroespacial (INTA); European Commission (EC); Agencia Estatal de Investigación (AEI)
Evolved stars are foundries of chemical complexity, gas and dust that provide the building blocks of planets and life, and dust nucleation first occurs in their photosphere. The circumstellar regions enveloping these stars, despite their importance, remain hidden to many observations, and dust formation processes are therefore still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. To reproduce and characterize the bottom-up dust formation process, we have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in situ characterization techniques. We show that carbonaceous dust analogues that formed from low-pressure gas-phase condensation of carbon atoms in a hydrogen atmosphere, in a ratio of carbon to molecular hydrogen similar to that reported for evolved stars, lead to the formation of amorphous carbon nanograins and aliphatic carbon clusters. Aromatic species and fullerenes do not form effectively under these conditions, raising implications for a revision of the chemical mechanisms taking place in circumstellar envelopes.
Acceso Abierto
Silicon and Hydrogen Chemistry under Laboratory Conditions Mimicking the Atmosphere of Evolved Stars
(IOP Science Publishing, 2021-01-05) Accolla, M.; Santoro, G.; Merino, P.; Martínez, L.; Tajuelo Castilla, G.; Vázquez, L.; Sobrado, J. M.; Agúndez, Marcelino; Jiménez Redondo, M.; Herrero, V. J.; Tanarro, I.; Cernicharo, J.; Martín Gago, J. A.; European Commission (EC); Ministerio de Economía y Competitividad (MINECO); Comunidad de Madrid; Accolla, M. [0000-0002-9509-5967]; Santoro, G. [0000-0003-4751-2209]; Merino, P. [0000-0002-0267-4020]; Martínez, L. [0000-0002-9370-2962]; Tajuelo Castilla, G. [0000-0001-7877-2543]; Vázquez, L. [0000-0001-6220-2810]; Sobrado, J. M. [0000-0002-7359-0262]; Agúndez, M. [0000-0003-3248-3564]; Herrero, V. J. [0000-0002-7456-4832]; Jiménez Redondo, M. [0000-0001-9221-8426]; Tanarro, I. [0000-0002-1888-513X]; Cernicharo, J. [0000-0002-3518-2524]; Martín Gago, J. A. [0000-0003-2663-491X]
Silicon is present in interstellar dust grains, meteorites and asteroids, and to date 13 silicon-bearing molecules have been detected in the gas phase toward late-type stars or molecular clouds, including silane and silane derivatives. In this work, we have experimentally studied the interaction between atomic silicon and hydrogen under physical conditions mimicking those in the atmosphere of evolved stars. We have found that the chemistry of Si, H, and H2 efficiently produces silane (SiH4), disilane (Si2H6) and amorphous hydrogenated silicon (a-Si:H) grains. Silane has been definitely detected toward the carbon-rich star IRC +10216, while disilane has not been detected in space yet. Thus, based on our results, we propose that gas-phase reactions of atomic Si with H and H2 are a plausible source of silane in C-rich asymptotic giant branch stars, although its contribution to the total SiH4 abundance may be low in comparison with the suggested formation route by catalytic reactions on the surface of dust grains. In addition, the produced a-Si:H dust analogs decompose into SiH4 and Si2H6 at temperatures above 500 K, suggesting an additional mechanism of formation of these species in envelopes around evolved stars. We have also found that the exposure of these dust analogs to water vapor leads to the incorporation of oxygen into Si–O–Si and Si–OH groups at the expense of SiH moieties, which implies that if this kind of grain is present in the interstellar medium, it will probably be processed into silicates through the interaction with water ices covering the surface of dust grains.
Restringido
Silicon Surface Nanostructuring for Covalent Immobilization of Biomolecules
(ACS Publications, 2008-06-03) Rogero, Celia; Chaffey, Benjamin T.; Mateo Martí, Eva; Sobrado, J. M.; Horrocks, Benjamin R.; Houlton, Andrew; Lakey, Jeremy H.; Briones, C.; Martín Gago, J. A.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN)
We present a straightforward strategy to control the average distance of immobilized biomolecules on silicon surfaces. We exploit the reaction taking place between the amino residues within the biomolecules (lysine groups of proteins or the N-terminus of oligomers of peptide nucleic acid, PNA) and the aldehyde-terminated groups presented in a mixed aldehyde/alkyl organic monolayer on a silicon surface. The mixed monolayers were prepared by a thermal reaction of hydrogen-terminated Si(111) with a mixture of undecene and undecenyl-aldehyde. We quantitatively evaluate the surface concentration of aldehyde in the monolayer by atomic force microscopy and an intensity analysis of core level X-ray photoemission spectroscopy peaks. These complementary techniques show that the surface density of the reactive terminal groups reflects the mole fraction of aldehyde in the reactive solution used to modify the silicon surface. The further immobilization of proteins or peptide nucleic acids on the monolayer shows that the density of biomolecules reproduces the aldehyde surface density, which indicates a specific covalent attachment and a negligible nonspecific adsorption. The proposed procedure makes possible to control the average distance of the immobilized active biomolecules on the silicon surface, which could be of great relevance for applications in the interdisciplinary field of biosensors.
Acceso Abierto
The Chemistry of Cosmic Dust Analogs from C, C2, and C2H2 in C-rich Circumstellar Envelopes
(The Institute of Physics (IOP), 2020-06-02) Santoro, G.; Martínez, L.; Lauwaet, K.; Accolla, M.; Tajuelo Castilla, G.; Merino, P.; Sobrado, J. M.; Peláez, R. J.; Herrero, V. J.; Tanarro, I.; Mayoral, Á.; Agúndez, Marcelino; Sabbah, H.; Joblin, C.; Cernicharo, J.; Martín Gago, J. A.; European Commission (EC); Comunidad de Madrid; Ministerio de Economía y Competitividad (MINECO); Santorio, G. [0000-0003-4751-2209]; Accolla, M. [0000-0002-9509-5967]; Agúndez, M. [0000-0003-3248-3564]; Sabbah, H. [0000-0001-5722-4388]; Joblin, C. [0000-0003-1561-6118]; Cernicharo, J. [0000-0002-3518-2524]; Martín Gago, J. M. [0000-0003-2663-491X]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch stars (AGBs). In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene, are the most abundant species after H and CO. In a previous study, we addressed the chemistry of carbon (C and C) with H showing that acetylene and aliphatic species form efficiently in the dust formation region of carbon-rich AGBs whereas aromatics do not. Still, acetylene is known to be a key ingredient in the formation of linear polyacetylenic chains, benzene, and polycyclic aromatic hydrocarbons (PAHs), as shown by previous experiments. However, these experiments have not considered the chemistry of carbon (C and C) with CH. In this work, by employing a sufficient amount of acetylene, we investigate its gas-phase interaction with atomic and diatomic carbon. We show that the chemistry involved produces linear polyacetylenic chains, benzene, and other PAHs, which are observed with high abundances in the early evolutionary phase of planetary nebulae. More importantly, we have found a nonnegligible amount of pure and hydrogenated carbon clusters as well as aromatics with aliphatic substitutions, both being a direct consequence of the addition of atomic carbon. The incorporation of alkyl substituents into aromatics can be rationalized by a mechanism involving hydrogen abstraction followed by methyl addition. All the species detected in the gas phase are incorporated into nanometric-sized dust analogs, which consist of a complex mixture of sp, sp, and sp hydrocarbons with amorphous morphology.
Acceso Abierto
Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept
(EDP Science, 2017-12-22) Tanarro, I.; Alemán, Belén; De Vicente, P.; Gallego, J. D.; Pardo, Juan R.; Santoro, G.; Lauwaet, K.; Tercero, Felix; Díaz Pulido, A.; Moreno, E.; Agúndez, Marcelino; Goicoechea, J. R.; Sobrado, J. M.; López, J. A.; Martínez, L.; Doménech, Jose Luis; Herrero, V. J.; Hernández, J. M.; Peláez, R. J.; López Pérez, Jose A.; Gómez González, J.; Alonso, J. L.; Jiménez, Elena; Teyssier, D.; Makasheva, Kremena; Castellanos, Marcelo; Joblin, C.; Martín Gago, J. A.; Cernicharo, J.; Ministerio de Economía y Competitividad (MINECO)
We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41–49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (<10-3 mbar) were detected in a few seconds. Fast data acquisition was achieved allowing for kinetic measurements in fragmentation experiments using electron impact or UV irradiation. Time evolution of chemical reactions involving OCS, O2 and CS2 was also observed demonstrating that reactive species, such as CS, can be maintained with high abundance in the gas phase during these experiments.