Publications 20212021-04-16T11:56:37+02:00

Publications (2021)

A dynamical (e,2e) investigation into the ionization of pyrazine

Authors: Jones, D. B.; Ali, E.; Chakraborty, H. S.; Ning, C. G.; Garcia, G.; Madison, D. H.; Brunger, M. J.

Journal: CHEMICAL PHYSICS LETTERS

Publication date: 2021/10/16

DOI: 10.1016/j.cplett.2021.139000

Abstract: We report an experimental and theoretical investigation into the dynamics of electron-impact ionization of the unresolved outermost molecular orbitals (6ag + 1b1g) of pyrazine (C4N2H4). Experimental triple differential cross sections (TDCS) are compared with cross sections calculated within a molecular 3-body distorted wave (M3DW) framework. The M3DW theory was able to reproduce the qualitative scattering behaviour in the binary region, but […]

Metal-catalyst-free gas-phase synthesis of long-chain hydrocarbons

Authors: Martinez, Lidia; Merino, Pablo; Santoro, Gonzalo; Martinez, Jose I.; Katsanoulis, Stergios; Ault, Jesse; Mayoral, Alvaro; Vazquez, Luis; Accolla, Mario; Dazzi, Alexandre; Mathurin, Jeremie; Borondics, Ferenc; Blazquez-Blazquez, Enrique; Shauloff, Nitzan; Lebron-Aguilar, Rosa; Quintanilla-Lopez, Jesus E.; Jelinek, Raz; Cernicharo, Jose; Stone, Howard A.; de la Pena O’Shea, Victor A.; de Andres, Pedro L.; Haller, George; Ellis, Gary J.; Martin-Gago, Jose A.

Journal: NATURE COMMUNICATIONS

Publication date: 2021/10/12

DOI: 10.1038/s41467-021-26184-0

Abstract: Development of sustainable processes for hydrocarbons synthesis is a fundamental challenge in chemistry since these are of unquestionable importance for the production […]

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Positron scattering from pyrazine

Authors: Edwards, D.; Stevens, D.; Cheong, Z.; Graves, V; Gorfinkiel, J. D.; Blanco, F.; Garcia, G.; Brunger, M. J.; White, R. D.; Sullivan, J. P.

Journal: PHYSICAL REVIEW A

Publication date: 2021/10/12

DOI: 10.1103/PhysRevA.104.042807

Abstract: The present paper provides a joint experimental and theoretical study of positron scattering from pyrazine. Experimental data were measured employing a low-energy positron beamline, and covered an energy range from 1 to 79 eV. Cross sections were measured for total scattering, total elastic scattering, positronium formation, direct ionization, and the sum of the total discrete electronic-state […]

Interstellar detection of the simplest aminocarbyne H2NC: an ignored but abundant molecule

Authors: Cabezas, C.; Agundez, M.; Marcelino, N.; Tercero, B.; Cuadrado, S.; Cernicharo, J.

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2021/10/07

DOI: 10.1051/0004-6361/202141491

Abstract: We report the first identification in space of H2NC, a high-energy isomer of H2CN that has been largely ignored in chemical and astrochemical studies. The observation of various unidentified lines around 72.2 GHz in the cold dark cloud L483 motivated the search and successful detection of additional groups of lines in harmonic relation. Following an exhaustive high-level ab initio screening of possible carriers, we confidently assign the unidentified […]

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Theoretical priors in scalar-tensor cosmologies: Shift-symmetric Horndeski models

Authors: Traykova, Dina; Bellini, Emilio; Ferreira, Pedro G.; Garcia-Garcia, Carlos; Noller, Johannes; Zumalacarregui, Miguel

Journal: PHYSICAL REVIEW D

Publication date: 2021/10/01

DOI: 10.1103/PhysRevD.104.083502

Abstract: Attempts at constraining theories of late time accelerated expansion often assume broad priors for the parameters in their phenomenological description. Focusing on shift-symmetric scalar-tensor theories with standard gravitational wave speed, we show how a more careful analysis of their dynamical evolution leads to much narrower priors. In doing so, we propose a simple and accurate parametrization of these theories, capturing the redshift dependence of the equation of […]

Imaging the elusive C-C bond dissociation channel of photoexcited ethyl radical

Authors: Marggi Poullain, Sonia; Rubio-Lago, Luis; Chicharro, David V.; Boullagui, Aymen; Zanchet, Alexandre; Yazidi, Ounaies; Garcia-Vela, Alberto; Banares, Luis

Journal: MOLECULAR PHYSICS

Publication date: 2021/10/01

DOI: 10.1080/00268976.2021.1984598

Abstract: The C-C bond dissociation channel of the ethyl (CH3-CH2) radical is investigated at 197.4, 199.98 and 201 nm by velocity map imaging and resonance enhanced multiphoton ionisation (REMPI) detection of the produced CH3 fragments. On the light of high-level ab initio calculations performed in this work, up to four dissociation pathways are identified leading, respectively, to ground state CH3 radicals in correlation with […]

Automatic design of quantum feature maps

Authors: Altares-Lopez, Sergio; Ribeiro, Angela; Garcia-Ripoll, Juan Jose

Journal: QUANTUM SCIENCE AND TECHNOLOGY

Publication date: 2021/10/01

DOI: 10.1088/2058-9565/ac1ab1

Abstract: We propose a new technique for the automatic generation of optimal ad-hoc ansatze for classification by using quantum support vector machine. This efficient method is based on non-sorted genetic algorithm II multiobjective genetic algorithms which allow both maximize the accuracy and minimize the ansatz size. It is demonstrated the validity of the technique by a practical example with a non-linear dataset, interpreting the resulting circuit and its outputs. We also show other […]

Encapsulation of a Water Molecule inside C-60 Fullerene: The Impact of Confinement on Quantum Features

Authors: Carrillo-Bohorquez, Orlando; Valdes, Alvaro; Prosmiti, Rita

Journal: JOURNAL OF CHEMICAL THEORY AND COMPUTATION

Publication date: 2021/09/14

DOI: 10.1021/acs.jctc.1c00662

Abstract: We introduce an efficient quantum fully coupled computational scheme within the multiconfiguration time-dependent Hartree (MCTDH) approach to handle the otherwise extremely costly computations of translational-rotational-vibrational states and energies of light-molecule endofullenes. Quantum calculations on energy levels are reported for a water molecule inside C-60 fullerene by means of such a systematic approach that includes all nine degrees of freedom of H2O@C-60 and does not consider restrictions above them. The potential energy […]

LiCl Photodissociation on Graphene: A Photochemical Approach to Lithium Intercalation

Authors: Azpeitia, Jon; Merino, Pablo; Ruiz-Gomez, Sandra; Foerster, Michael; Aballe, Lucia; Garcia-Hernandez, Mar; Angel Martin-Gago, Jose; Palacio, Irene

Journal: ACS APPLIED MATERIALS & INTERFACES

Publication date: 2021/09/08

DOI: 10.1021/acsami.1c11654

Abstract: The interest in the research of the structural and electronic properties between graphene and lithium has bloomed since it has been proven that the use of graphene as an anode material in lithium-ion batteries ameliorates their performance and stability. Here, we investigate an alternative route to intercalate lithium underneath epitaxially grown graphene on iridium by means of photon irradiation. We grow […]

Atomic-Scale Structural Fluctuations of a Plasmonic Cavity

Authors: Roslawska, Anna; Merino, Pablo; Grewal, Abhishek; Leon, Christopher C.; Kuhnke, Klaus; Kern, Klaus

Journal: NANO LETTERS

Publication date: 2021/09/08

DOI: 10.1021/acs.nanolett.1c02207

Abstract: Optical spectromicroscopies, which can reach atomic resolution due to plasmonic enhancement, are perturbed by spontaneous intensity modifications. Here, we study such fluctuations in plasmonic electroluminescence at the single-atom limit profiting from the precision of a low-temperature scanning tunneling microscope. First, we investigate the influence of a controlled single-atom transfer from the tip to the sample on the plasmonic properties of the junction. Next, we form a well-defined atomic […]

DEATHSTAR: nearby AGB stars with the Atacama Compact Array II. CO envelope sizes and asymmetries: the S-type stars

Authors: Andriantsaralaza, M.; Ramstedt, S.; Vlemmings, W. H. T.; Danilovich, T.; De Beck, E.; Groenewegen, M. A. T.; Hofner, S.; Kerschbaum, F.; Khouri, T.; Lindqvist, M.; Maercker, M.; Olofsson, H.; Quintana-Lacaci, G.; Saberi, M.; Sahai, R.; Zijlstra, A.

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2021/09/07

DOI: 10.1051/0004-6361/202140952

Abstract: Aims. We aim to constrain the sizes of, and investigate deviations from spherical symmetry in, the CO circumstellar envelopes (CSEs) of 16 S-type stars, along with an additional 7 and 4 CSEs of C-type and M-type AGB stars, respectively. Methods. We map the […]

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Magnesium radicals MgC5N and MgC6H in IRC+10216

Authors: Pardo, J. R.; Cabezas, C.; Fonfria, J. P.; Agundez, M.; Tercero, B.; de Vicente, P.; Guelin, M.; Cernicharo, J.

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2021/08/31

DOI: 10.1051/0004-6361/202141671

Abstract: After the previous discovery of MgC3N and MgC4H in IRC +10216, a deeper Q-band (31.0-50.3 GHz) integration on this source had revealed two additional series of harmonically related doublets that we assigned on the basis of quantum mechanical calculations to the larger radicals MgC5N and MgC6H. The results presented here extend and confirm previous results on magnesium-bearing molecules in IRC +10216. […]

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Versatile Atomic Magnetometry Assisted by Bayesian Inference

Authors: Puebla, R.; Ban, Y.; Haase, J. F.; Plenio, M. B.; Paternostro, M.; Casanova, J.

Journal: PHYSICAL REVIEW APPLIED

Publication date: 2021/08/25

DOI: 10.1103/PhysRevApplied.16.024044

Abstract: Quantum sensors typically translate external fields into a periodic response whose frequency is then determined by analyses performed in Fourier space. This allows for a linear inference of the parameters that characterize external signals. In practice, however, quantum sensors are able to detect fields only in a narrow range of amplitudes and frequencies. A departure from this range, as well as the presence of significant noise […]

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Discovery of benzyne, o-C6H4, in TMC-1 with the QUIJOTE line survey

Authors: Cernicharo, J.; Agundez, M.; Kaiser, R. I.; Cabezas, C.; Tercero, B.; Marcelino, N.; Pardo, J. R.; de Vicente, P.

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2021/08/18

DOI: 10.1051/0004-6361/202141660

Abstract: We report the detection, for the first time in space, of a new non-functionalised hydrocarbon cycle in the direction of TMC-1: o-C6H4 (ortho-benzyne). We derive a column density for this hydrocarbon cycle of (5.0 +/- 1.0) x 10(11) cm(-2). The abundance of this species is around 30 times lower than that of cyclopentadiene and indene. We compare the abundance of benzyne […]

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Observation and calibration strategies for large-scale multi-beam velocity-resolved mapping of the [CII] emission in the Orion molecular cloud

Authors: Higgins, R.; Kabanovic, S.; Pabst, C.; Teyssier, D.; Goicoechea, J. R.; Berne, O.; Chambers, E.; Wolfire, M.; Suri, S. T.; Buchbender, C.; Okada, Y.; Mertens, M.; Parikka, A.; Aladro, R.; Richter, H.; Gusten, R.; Stutzki, J.; Tielens, A. G. G. M.

Journal: ASTRONOMY & ASTROPHYSICS

Publication date: 2021/08/12

DOI: 10.1051/0004-6361/202039621

Abstract: Context. The [CII] 158 mu m far-infrared fine-structure line is one of the dominant cooling lines of the star-forming interstellar medium. Hence [CII] emission originates in and thus can be used to trace a range of ISM processes. Velocity-resolved […]

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