Publications 2020

Publications 20202020-12-11T18:22:11+01:00

Publications (2020)

Publications sorted by date descending

A comparison of experimental and theoretical low energy positron scattering from furan

Authors: Cheong, Z.; Moreira, G. M.; Bettega, M. H. F.; Blanco, F.; Garcia, G.; Brunger, M. J.; White, R. D.; Sullivan, J. P.

Contribution: Article

Journal: JOURNAL OF CHEMICAL PHYSICS

Publication date: 2020/12/28

DOI: 10.1063/5.0027874

Abstract: This paper presents a joint experimental and theoretical study of positron scattering from furan. Experimental data were measured using the low energy positron beamline located at the Australian National University and cover an energy range from 1 eV to 30 eV. Cross sections were measured for total scattering, total elastic and inelastic scattering, positronium formation, […]

Tracers of the ionization fraction in dense and translucent gas: I. Automated exploitation of massive astrochemical model grids

Authors: Bron, Emeric; Roueff, Evelyne; Gerin, Maryvonne; Pety, Jerome; Gratier, Pierre; Le Petit, Franck; Guzman, Viviana; Orkisz, Jan H.; Magalhaes, Victor de Souza; Gaudel, Mathilde; Vono, Maxime; Bardeau, Sebastien; Chainais, Pierre; Goicoechea, Javier R.; Hughes, Annie; Kainulainen, Jouni; Languignon, David; Le Bourlot, Jacques; Levrier, Francois; Liszt, Harvey; Oberg, Karin; Peretto, Nicolas; Roueff, Antoine; Sievers, Albrecht

Contribution: Article

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2020/12/23

DOI: 10.1051/0004-6361/202038040

Abstract: Context. The ionization fraction in the neutral interstellar medium (ISM) plays a key role in the physics and chemistry of the ISM, from controlling […]

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Quantitative inference of the H2 column densities from 3mm molecular emission: case study towards Orion B

Authors: Gratier, Pierre; Pety, Jerome; Bron, Emeric; Roueff, Antoine; Orkisz, Jan H.; Gerin, Maryvonne; Magalhaes, Victor de Souza; Gaudel, Mathilde; Vono, Maxime; Bardeau, Sebastien; Chanussot, Jocelyn; Chainais, Pierre; Goicoechea, Javier R.; Guzman, Viviana V.; Hughes, Annie; Kainulainen, Jouni; Languignon, David; Le Bourlot, Jacques; Le Petit, Franck; Levrier, Francois; Liszt, Harvey; Peretto, Nicolas; Rouefe, Evelyne; Sievers, Albrecht

Contribution: Article

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2020/12/23

DOI: 10.1051/0004-6361/202037871

Abstract: Context. Based on the finding that molecular hydrogen is unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely […]

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(CO)-O-18, (CO)-C-13, and (CO)-C-12 abundances and excitation temperatures in the Orion B molecular cloud: Analysis of the achievable precision in modeling spectral lines within the approximation of the local thermodynamic equilibrium

Authors: Roueff, Antoine; Gerin, Maryvonne; Gratier, Pierre; Levrier, Francois; Pety, Jerome; Gaudel, Mathilde; Goicoechea, Javier R.; Orkisz, Jan H.; Magalhaes, Victor de Souza; Vono, Maxime; Bardeau, Sebastien; Bron, Emeric; Chanussot, Jocelyn; Chainais, Pierre; Guzman, Viviana V.; Hughes, Annie; Kainulainen, Jouni; Languignon, David; Le Bourlot, Jacques; Le Petit, Franck; Liszt, Harvey S.; Marchal, Antoine; Miville-Deschenes, Marc-Antoine; Peretto, Nicolas; Roueff, Evelyne; Sievers, Albrecht

Contribution: Article

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2020/12/23

DOI: 10.1051/0004-6361/202037776

Abstract: Context. CO isotopologue transitions are routinely observed in molecular clouds for the purpose of probing the column density […]

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CF+ excitation in the interstellar medium

Authors: Desrousseaux, Benjamin; Lique, Francois; Goicoechea, Javier R.; Quintas-Sanchez, Ernesto; Dawes, Richard

Contribution: Article

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2020/12/21

DOI: 10.1051/0004-6361/202039823

Abstract: The detection of CF+ in interstellar clouds potentially allows astronomers to infer the elemental fluorine abundance and the ionization fraction in ultraviolet-illuminated molecular gas. Because local thermodynamic equilibrium (LTE) conditions are hardly fulfilled in the interstellar medium (ISM), the accurate determination of the CF+ abundance requires one to model its non-LTE excitation via both radiative and collisional processes. Here, we report quantum calculations of rate coefficients for […]

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Invariant-based inverse engineering of time-dependent, coupled harmonic oscillators

Authors: Tobalina, A.; Torrontegui, E.; Lizuain, I; Palmero, M.; Muga, J. G.

Contribution: Article

Journal: PHYSICAL REVIEW A

Publication date: 2020/12/14

DOI: 10.1103/PhysRevA.102.063112

Abstract: Two-dimensional (2D) systems with time-dependent controls admit a quadratic Hamiltonian modeling near potential minima Independent, dynamical normal modes facilitate inverse Hamiltonian engineering to control the system dynamics, but some systems are not separable into independent modes by a point transformation. For these “coupled systems” 2D invariants may still guide the Hamiltonian design. The theory to perform the inversion and two application examples are provided: (i) We control […]

Rotational spectroscopic study of S-methyl thioformate: A global laboratory analysis of ground and excited torsional states up to 660 GHz

Authors: Jabri, A.; Tercero, B.; Margules, L.; Motiyenko, R. A.; Alekseev, E. A.; Kleiner, I.; Cernicharo, J.; Guillemin, J. -C.

Contribution: Article

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2020/12/07

DOI: 10.1051/0004-6361/202038200

Abstract: Context. S-methyl thioformate CH3SC(O)H is a monosulfur derivative of methyl formate, a relatively abundant component of the interstellar medium (ISM). S-methyl thioformate being, thermodynamically, the most stable isomer, it can be reasonably proposed for detection in the ISM.Aims. This work aims to experimentally study and theoretically analyze the ground and first torsional excited states for CH3SC(O)H in a large […]

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INFRA-ICE: An ultra-high vacuum experimental station for laboratory astrochemistry

Authors: Santoro, Gonzalo; Sobrado, Jesus M.; Tajuelo-Castilla, Guillermo; Accolla, Mario; Martinez, Lidia; Azpeitia, Jon; Lauwaet, Koen; Cernicharo, Jose; Ellis, Gary J.; Angel Martin-Gago, Jose

Contribution: Article

Journal: REVIEW OF SCIENTIFIC INSTRUMENTS

Publication date: 2020/12/01

DOI: 10.1063/5.0027920

Abstract: 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 […]

Rotational spectra of van der Waals complexes: pyrrole-Ne and pyrrole-Ne-2

Authors: Peña, Isabel; Cabezas, Carlos

Contribution: Article

Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Publication date: 2020/11/28

DOI: 10.1039/d0cp04580b

Abstract: The van der Waals 1 : 1 and 1 : 2 adducts between the aromatic molecule pyrrole (Pyr) and the rare gas atom neon (Ne) have been investigated using a combination of chirped pulse Fourier transform microwave spectroscopy and quantum-chemical calculations. Rotational spectra of two and three isotopologues of Pyr-Ne and Pyr-Ne-2, respectively, arising from the combinations of the Ne-20 and Ne-22 isotopes, were identified and a partial r(s) structure determined. Unusual spectral […]

Detection of infrared fluorescence of carbon dioxide in R Leonis with SOFIA/EXES

Authors: Fonfria, J. P.; Montiel, E. J.; Cernicharo, J.; DeWitt, C. N.; Richter, M. J.

Contribution: Article

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2020/11/23

DOI: 10.1051/0004-6361/202039547

Abstract: We report on the detection of hot CO2 in the O-rich asymptotic giant branch star R Leo based on high spectral resolution observations in the range 12.8-14.3 mu m carried out with the Echelon-cross-Echelle Spectrograph (EXES) mounted on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We found similar or equal to 240 CO2 emission lines in several vibrational bands. These detections were possible thanks […]

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Scaling up the Anderson transition in random-regular graphs

Authors: Pino, M.

Contribution: Article

Journal: PHYSICAL REVIEW RESEARCH

Publication date: 2020/11/20

DOI: 10.1103/PhysRevResearch.2.042031

Abstract: We study the Anderson transition in lattices with the connectivity of a random-regular graph. Our results show that fractal dimensions are continuous across the transition, but a discontinuity occurs in their derivatives, implying the existence of a nonergodic metallic phase with multifractal eigenstates. The scaling analysis gives critical exponent nu = 0.94 +/- 0.08 and critical disorder W-c = 18.17 +/- 0.02. Our data support that ergodicity is only recovered at zero disorder.

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Projected Entangled Pair States: Fundamental Analytical and Numerical Limitations

Authors: Scarpa, G.; Molnar, A.; Ge, Y.; Garcia-Ripoll, J. J.; Schuch, N.; Perez-Garcia, D.; Iblisdir, S.

Contribution: Article

Journal: PHYSICAL REVIEW LETTERS

Publication date: 2020/11/20

DOI: 10.1103/PhysRevLett.125.210504

Abstract: Matrix product states and projected entangled pair states (PEPS) are powerful analytical and numerical tools to assess quantum many-body systems in one and higher dimensions, respectively. While matrix product states are comprehensively understood, in PEPS fundamental questions, relevant analytically as well as numerically, remain open, such as how to encode symmetries in full generality, or how to stabilize numerical methods using canonical forms. […]

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Selective bond breaking of halothane induced by electron transfer in potassium collisions

Authors: Lozano, A. I.; Maioli, L. S.; Pamplona, B.; Romero, J.; Mendes, M.; Ferreira da Silva, F.; Kossoski, F.; Probst, M.; Suess, D.; Bettega, M. H. F.; Garcia, G.; Limao-Vieira, P.

Contribution: Article

Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Publication date: 2020/11/07

DOI: 10.1039/d0cp02570d

Abstract: We present novel experimental results of negative ion formation of halothane (C2HBrClF3) upon electron transfer from hyperthermal neutral potassium atoms (K degrees) in the collision energy range of 8-1000 eV. The experiments were performed in a crossed molecular beam setup allowing a comprehensive analysis of the time-of-flight […]

Experimental and theoretical studies of the N(D-2) + H-2 and D-2 reactions

Authors: Nuñez-Reyes, Dianailys; Bray, Cedric; Hickson, Kevin M.; Larregaray, Pascal; Bonnet, Laurent; Gonzalez-Lezana, Tomas

Contribution: Article

Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Publication date: 2020/11/07

DOI: 10.1039/d0cp03971c

Abstract: This study reports the results of an experimental and theoretical investigation of the N(D-2) + H-2 and N(D-2) + D-2 reactions at room temperature and below. On the experimental side, a supersonic flow (Laval nozzle) reactor was employed to measure rate constants for these processes at temperatures as low as 127 K. N(D-2) was produced indirectly by pulsed laser photolysis and these atoms were […]

Structural Stability of the CO2@sI Hydrate: a Bottom-Up Quantum Chemistry Approach on the Guest-Cage and Inter-Cage Interactions

Authors: Cabrera-Ramirez, Adriana; Arismendi-Arrieta, Daniel J.; Valdes, Alvaro; Prosmiti, Rita

Contribution: Article; Early Access

Journal: CHEMPHYSCHEM

Publication date: 2020/11/01

DOI: 10.1002/cphc.202000753

Abstract: Through reliable first-principles computations, we have demonstrated the impact of CO2 molecules enclathration on the stability of sI clathrate hydrates. Given the delicate balance between the interaction energy components (van der Waals, hydrogen bonds) present on such systems, we follow a systematic bottom-up approach starting from the individual 5(12) and 5(12)6(2) sI cages, up to all existing combinations of two-adjacent sI crystal cages to evaluate how such clathrate-like models […]

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