A5055686675- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Molecular Spectroscopy and Structure
- Astrophysics and Star Formation Studies
- Advanced Chemical Physics Studies
- Astro and Planetary Science
- Spectroscopy and Quantum Chemical Studies
- Atmospheric chemistry and aerosols
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Molecular spectroscopy and chirality
- Thermodynamic properties of mixtures
- Gas Sensing Nanomaterials and Sensors
- Inorganic Fluorides and Related Compounds
- Crystallography and molecular interactions
- Chemical Thermodynamics and Molecular Structure
- Solid-state spectroscopy and crystallography
- Atomic and Molecular Physics
- Phase Equilibria and Thermodynamics
- nanoparticles nucleation surface interactions
- Analytical Chemistry and Sensors
- Diamond and Carbon-based Materials Research
- Spacecraft and Cryogenic Technologies
- High-pressure geophysics and materials
- Mass Spectrometry Techniques and Applications
Universidad Complutense de Madrid
1993-2021
Instituto de Estructura de la Materia
2011-2020
Consejo Superior de Investigaciones Científicas
2006-2019
Universidad Politécnica de Madrid
2013-2018
University of British Columbia
2013
National Research Council
2009-2010
University of the Basque Country
2009
University of Cambridge
2006-2008
Conference Board
2006
Universidad de Jaén
2005
From the frontiers of research on ice dynamics in its broadest sense, this review surveys structures ice, patterns or morphologies it may assume, and physical chemical processes which is involved. Open questions various fields nature are highlighted, ranging from terrestrial oceanic Earth, to atmosphere, other Solar System bodies interstellar space.
Carbon dioxide (CO 2 ) is one of the most relevant and abundant species in astrophysical atmospheric media. In particular, CO ice present several solar system bodies, as well interstellar circumstellar mantles. The amount mantles presence pure are significant indicators temperature history dust protostars. It therefore important to know if mixed with other molecules matrix or segregated whether it an amorphous crystalline form. We apply a multidisciplinary approach involving IR spectroscopy...
The conversion from neutral to zwitterionic glycine is studied using infrared spectroscopy the point of view interactions this molecule with polar (water) and non-polar (CO2, CH4) surroundings. Such environments could be found on astronomical or astrophysical matter. samples are prepared by vapour-deposition a cold substrate (25 K), then heated up sublimation temperatures co-deposited species. At 25 K, species favoured over form in environments, whereas for pure glycine, glycine/water...
We present the Infrared Space Observatory/Short-Wavelength Spectrometer full grating resolution spectrum of IRC +10216, which is dominated by strong absorption/emission bands C2H2 and HCN. All near-infrared stretching HCN are observed in absorption, whereas fundamental, hot, combination involving ν2 bending mode around 14 μm emission. Particularly = 20 → 11 vibrational transition at 14.3 μm. The most plausible mechanism for such emission radiative pumping molecules from ground to state (7.1...
Abstract The absolute Raman intensities and depolarization ratios of all the fundamental bands CH2Cl2, CD2Cl2 CHDCl2 have been measured in gas phase. These experimental data included a refinement vibrational potential function dichloromethanes. A detailed description is made use bond polarizability approach. Explicit expressions for derivatives molecular with respect to symmetry coordinates are given terms zeroth- first-order electro-optical parameters theory. Good agreement found between...
A b initio values of ν1, ν3 and the zero point energy for triplet methylene (X̃ 3B1 CH2) have been calculated. Complete second order configuration interaction calculations six valence electrons, with a Davidson-type unlinked cluster correction, were done at 37 selected nuclear geometries. We fitted an analytic potential through these points used nonrigid bender Hamiltonian, variational procedure, to calculate rotation–vibration energies. obtained ν1=2985±20 cm−1, ν3=3205±20 as 3710±20 cm−1....
Aims.We studied the interaction between CO2 (guest) and H2O (host) molecular ices.
Ice mixtures of methane and water are investigated by means IR spectroscopy in the 14-60 K range. The spectroscopic research is focused on symmetry-forbidden nu(1) band CH(4) dangling bond bands water. visible spectra mixtures, revealing a distorted structure which co-exists with normal crystalline methane. found to increase their intensity appear at red-shifted frequency when present. Methane adsorbed micropores or trapped inside amorphous solid assumed be responsible for these effects....
The solid phases of methanol were investigated using IR spectroscopy and numerical calculations with the SIESTA method. Improved spectra are reported amorphous at 90 K, in particular alpha beta 130 165 respectively, assignments bands not previously measured. main features each phase discussed compared. A study spectral changes temperature leads to conclusion that metastable might be a mixture two known stable phases. Such could explain all observed this investigation. theoretical provide...
The effect of UV photon (120-200 nm) and electron (2 keV) irradiation analogues interstellar carbonaceous dust glycine were investigated by means IR spectroscopy. Films hydrogenated amorphous carbon (HAC), taken as analogues, found to be stable under bombardment. High fluences photons electrons, the order 10(19) cm(-2), needed for a film depletion few percent. energetically more effective than electrons led certain dehydrogenation HAC samples, whereas seemingly gradual erosion with no...
A systematic investigation of amorphous and crystalline vapor deposited ice layers with thickness ranging from less than 100 nm to more 5 μm has been performed using Fourier transform (FT) reflection−absorption infrared spectroscopy (RAIRS). Al Au surfaces were used for the deposition very similar results obtained on both. The spectra recorded both polarized nonpolarized radiation simulated a simple Fresnel reflection model empirical optical indices literature. Optical effects peculiar this...
The spectra of nitric acid and monohydrate crystals, including both vibration frequencies infrared intensities, have been calculated from first principles using the methodology developed for SIESTA program. In this method, intensities are evaluated macroscopic polarization changes with atomic displacements per normal mode. process requires calculation Born charges associated displacements. actual value tensor elements gives interesting information on electronic nature bonds. application...
The so-called hyperquenching technique has been applied to generate water ices containing ammonium and formate ions by sudden freezing of droplets NH4Cl, NH4COOH, NaCOOH solutions. Salt deposits were obtained after heating the 210 K sublimate all content. All stages are controlled IR transmission spectroscopy. NH4+ bands very much broadened smeared in frozen droplets, but stand out strongly when is eliminated. This fact hints toward difficulty ascertaining presence this species astrophysical...
We measure the band strengths in far-infrared region of interstellar ice analogs astrophysically relevant species, such as H$_2$O, CO$_2$, CH$_3$OH, and NH$_3$, deposited at low temperature (8-10 $\mathrm{K}$), followed by warm-up, to induce amorphous-crystalline phase transitions when relevant. The spectra pure CH$_3$OH ices have been measured near-, mid- spectroscopic regions using Interstellar Astrochemistry Chamber (ISAC) ultra-high-vacuum setup. In addition, NH$_3$ CO$_2$ were a...
Ammonia ice has been detected on different astrophysical media ranging from interstellar medium (ISM) particles to the surface of various icy bodies our solar system, where nitrogen is also present. We have carried out a detailed study amorphous NH3 and NH3:N2 mixtures, based infrared (IR) spectra in mid-IR (MIR) near-IR (NIR) regions, supported by theoretical quantum chemical calculations. Spectra varying thicknesses were obtained optical constants calculated for at 15 K 30 mixture over...
The destruction of solid glycine under irradiation with 2 keV electrons has been investigated by means IR spectroscopy. Destruction cross sections, radiolysis yields, and half-life doses were determined for samples at 20, 40, 90, 300 K. thickness the irradiated was kept below estimated penetration depth electrons. No significant differences obtained in experiments 90 K, but section K larger a factor 2. yields are good accordance recent MeV proton experiments, which confirms that range can be...
The molecular complexes formed by nitric acid with one, two, and three water molecules have been investigated high level ab initio calculations. B3LYP/aug-cc-pVTZ method basis set used to derive equilibrium geometries binding energies predict the infrared spectra of these complexes. It has found that become stable through formation several hydrogen bonds. main one is established between acid, which acts as a donor, first molecule, but further bonds are created successive molecules, weaker...
The à 1B1–X̃ 1A1 absorption spectrum of SiH2 has been observed using intracavity laser spectroscopy with an equivalent path length up to 13.0 km and the 1B1(0, 0, 0)–X̃ 1A1(0, 0) band near 640 nm recorded for first time. silylene radical was generated in a continuous discharge flowing mixture silane argon, giving concentration order 1010 SiH2/cm3. spans region between 15350 16100 cm−1. Rotational transitions have assigned levels J=16 Ka=9, ΔKa 5, ΔKc 4. Perturbations detected spectrum, due...
Recent observations of CH4 in different astrophysical objects encourage laboratory research on methane/water ice mixtures. An IR spectroscopy investigation is presented these systems. Co-deposited samples are formed by vapor deposition and H2O a cold substrate, wide range stoichiometries, from very diluted mixtures to CH4/H2O = 2.5 values. Samples prepared at 14 K 40 K, their temperature behavior studied when they warmed up 60 K. The spectroscopic analysis centered the methane features, also...