Publications 2019

Publications 20192020-01-30T15:23:08+01:00

Publications (2019)

Publications sorted by date descending

Positron interactions with nitrogen and oxygen molecules: elastic, inelastic and total cross sections

Authors: Ellis-Gibbings, Lilian; Blanco, Francisco; Garcia, Gustavo

Contribution: Article


Publication date: 2019/12/23

DOI: 10.1140/epjd/e2019-100459-x

Abstract: Positron scattering cross sections, used for modelling particle transport in various media, are difficult to gather experimentally. As such, various cross section calculation methods have been developed to varying accuracy. The IAM-SCAR+I method has been improved upon recently to fulfil the optical theorem and the results for two important simple molecules, N-2 and O-2, are presented here. These results are compared to literature and our findings are comparable in most […]

Dynamics of H + HeH+(v=0, j=0) -> H-2(+) + He: Insight on the Possible Complex-Forming Behavior of the Reaction

Authors: Gonzalez-Lezana, Tomas; Bossion, Duncan; Scribano, Yohann; Bhowmick, Somnath; Suleimanov, Yury, V

Contribution: Article


Publication date: 2019/12/12

DOI: 10.1021/acs.jpca.9b06122

Abstract: The H + HeH+ -> He + H-2(+) reaction has been studied by means of a combination of theoretical approaches: a statistical quantum method (SQM), ring polymer molecular dynamics (RPMD), and the quasiclassical trajectory (QCT) method. Cross sections and rate constants have been calculated in an attempt to investigate the dynamics of the process. The comparison with previous calculations and experimental results reveals that […]

Charge Carrier Injection Electroluminescence with CO-Functionalized Tips on Single Molecular Emitters

Authors: Dolezal, Jiri; Merino, Pablo; Redondo, Jesus; Ondic, Lukas; Cahlik, Ales; Svec, Martin

Contribution: Article


Publication date: 2019/12/01

DOI: 10.1021/acs.nanolett.9b03180

Abstract: We investigate electroluminescence of single molecular emitters on NaCl on Ag(111) and Au(111) with submolecular resolution in a low-temperature scanning probe microscope with tunneling current, atomic force, and light detection capabilities. The role of the tip state is studied in the photon maps of a prototypical emitter, zinc phthalocyanine (ZnPc), using metal and CO-metal tips. CO-functionalization is found to have an impact on the resolution and […]

Interaction of photoionisation and meteoric input in the atmosphere of Jupiter

Authors: Campbell, Laurence; Jones, Darryl B.; White, Ronald D.; Garcia, Gustavo; Ingolfsson, Oddur; Lopes, M. Cristina A.; Brunger, Michael J.

Contribution: Article


Publication date: 2019/12/01

DOI: 10.1140/epjd/e2019-100466-y

Abstract: Interplanetary dust grains and meteoroids are assumed to deliver oxygen to the atmosphere of Jupiter. A current photochemical model overestimates the resultant density of water relative to an available measurement. This paper investigates whether the interaction of photoionisation and meteoric products can explain that discrepancy. As any process that breaks up water molecules is likely to produce […]

Floquet-Engineered Vibrational Dynamics in a Two-Dimensional Array of Trapped Ions

Authors: Kiefer, Philip; Hakelberg, Frederick; Wittemer, Matthias; Bermudez, Alejandro; Porras, Diego; Warring, Ulrich; Schaetz, Tobias

Contribution: Article


Publication date: 2019/11/21

DOI: 10.1103/PhysRevLett.123.213605

Abstract: We demonstrate Floquet engineering in a basic yet scalable 2D architecture of individually trapped and controlled ions. Local parametric modulations of detuned trapping potentials steer the strength of long-range interion couplings and the related Peierls phase of the motional state. In our proof of principle, we initialize large coherent states and tune modulation parameters to control trajectories, directions, and interferences of the phonon […]

Tags: , |

Revisiting the photoabsorption spectrum of NH3 in the 5.4-10.8 eV energy region

Authors: Limao-Vieira, P.; Jones, N. C.; Hoffmann, S. V.; Duflot, D.; Mendes, M.; Lozano, A. I.; Ferreira da Silva, F.; Garcia, G.; Hoshino, M.; Tanaka, H.

Contribution: Article


Publication date: 2019/11/14

DOI: 10.1063/1.5128051

Abstract: We present a comprehensive revisited experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of ammonia, NH3, covering for the first time the full 5.4-10.8 eV energy-range, with absolute cross sections determined. The calculations on the vertical excitation energies and oscillator strengths were performed using the equation-of-motion coupled cluster method restricted to single […]

The 3s versus 3p Rydberg state photodissociation dynamics of the ethyl radical

Authors: Marggi Poullain, Sonia; Chicharro, David V.; Zanchet, Alexandre; Rubio-Lago, Luis; Garcia-Vela, Alberto; Bañares, Luis

Contribution: Article


Publication date: 2019/11/07

DOI: 10.1039/c9cp04273c

Abstract: The photodissociation dynamics of the ethyl radical following excitation into the 3s and 3p Rydberg states are revisited in a joint experimental and theoretical study. Two different methods to produce the ethyl radical, pyrolysis and in situ photolysis, are employed in order to modify the initial ro-vibrational energy distribution characterizing the ethyl radical beam. H-atom velocity map images following excitation of the […]

On the Stability of Cu-5 Catalysts in Air Using Multireference Perturbation Theory

Authors: Zanchet, Alexandre; Lopez-Caballero, Patricia; Mitrushchenkov, Alexander O.; Buceta, David; Arturo Lopez-Quintela, Manuel; Hauser, Andreas W.;  de Lara-Castells, Maria Pilar

Contribution: Article


Publication date: 2019/11/07

DOI: 10.1021/acs.jpcc.9b08378

Abstract: An ab initio study of the interaction of O-2, the most abundant radical and oxidant species in the atmosphere, with a Cu-5 cluster, a new generation atomic metal catalyst, is presented. The open-shell nature of the reactant species is properly accounted for by using the multireference perturbation theory, allowing the experimentally confirmed resistivity of Cu-5 clusters […]

Cold atoms in twisted-bilayer optical potentials

Authors: Gonzalez-Tudela, A.; Cirac, J., I

Contribution: Article


Publication date: 2019/11/06

DOI: 10.1103/PhysRevA.100.053604

Abstract: The possibility of creating crystal bilayers twisted with respect to each other has led to the discovery of a wide range of novel electron correlated phenomena the full understanding of which is still under debate. Here we propose and analyze a method to simulate twisted bilayers using cold atoms in state-dependent optical lattices. Our proposed setup can be used as an alternative platform to explore twisted bilayers which allows one to control […]

Shortcuts to adiabaticity: Concepts, methods, and applications

Authors: Guery-Odelin, D.; Ruschhaupt, A.; Kiely, A.; Torrontegui, E.; Martinez-Garaot, S.; Muga, J. G.

Contribution: Review


Publication date: 2019/10/24

DOI: 10.1103/RevModPhys.91.045001

Abstract: Shortcuts to adiabaticity (STA) are fast routes to the final results of slow, adiabatic changes of the controlling parameters of a system. The shortcuts are designed by a set of analytical and numerical methods suitable for different systems and conditions. A motivation to apply STA methods to quantum systems is to manipulate them on timescales shorter than decoherence times. Thus shortcuts to adiabaticity […]

Tags: , |

Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes

Authors: Martínez, L.; Santoro, G.; Merino, P.; Accolla, M.; Lauwaet, K.; Sobrado, J.; Sabbah, H.; Peláez, R. J.; Herrero, V. J.; Tanarro, I.; Agúndez, M.; Martín-Jiménez, A.; Otero, R.; Ellis, G. J.; Joblin, C.; Cernicharo, J.; Martín-Gago, J. A.

Contribution: Article


Publication date: 2019/10/21

DOI: 10.1038/s41550-019-0899-4

Abstract: 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 […]

Tags: |

Quantum Effects on the D + H-3(+) -> H2D+ + H Deuteration Reaction and Isotopic Variants

Authors: Bulut, Niyazi; Aguado, Alfredo; Sanz-Sanz, Cristina; Roncero, Octavio

Contribution: Article


Publication date: 2019/10/17

DOI: 10.1021/acs.jpca.9b06081

Abstract: The title reaction and its isotopic variants are studied using quasi-classical trajectory (QCT) (without taking into account corrections to account for the possible zero point energy breakdown) and ring polymer molecular dynamics (RPMD) methods with a full dimensional and accurate potential energy surface which presents an exchange barrier of approximately 0.144 eV. The QCT rate constant increases when the temperature decreases from 1500 to 10 K. On […]

Symmetries and conservation laws in quantum trajectories: Dissipative freezing

Authors: Muñoz, Carlos Sanchez; Buca, Berislav; Tindall, Joseph; Gonzalez-Tudela, Alejandro; Jaksch, Dieter; Porras, Diego

Contribution: Article


Publication date: 2019/10/16

DOI: 10.1103/PhysRevA.100.042113

Abstract: In driven-dissipative systems, the presence of a strong symmetry guarantees the existence of several steady states belonging to different symmetry sectors. Here we show that when a system with a strong symmetry is initialized in a quantum superposition involving several of these sectors, each individual stochastic trajectory will randomly select a single one of them and remain there for the rest of the evolution. […]

Ultrastrong-coupling circuit QED in the radio-frequency regime

Authors: Jaako, T.; Garcia-Ripoll, J. J.; Rabl, P.

Contribution: Article


Publication date: 2019/10/11

DOI: 10.1103/PhysRevA.100.043815

Abstract: We study a circuit QED setup where multiple superconducting qubits are ultrastrongly coupled to a single radio-frequency resonator. In this extreme parameter regime of cavity QED the dynamics of the electromagnetic mode is very slow compared to all other relevant timescales and can be described as an effective particle moving in an adiabatic energy landscape defined by the qubits. The focus of this paper is placed on settings with two […]

Inelastic Collisions of O-2 with He at Low Temperatures

Authors: Gámez, F.; Fernandez, J. M.; Moreno, E.; Tejeda, G.; Hernandez, M. I.; Montero, S.

Contribution: Article


Publication date: 2019/10/10

DOI: 10.1021/acs.jpca.9b06165

Abstract: Rotationally inelastic collisions of O-2 with He in the 10-34 K thermal range are investigated by means of an experimental procedure based on supersonic gas jets probed by Raman spectroscopy. The procedure employs a kinetic master equation (MEQ) that describes the time evolution of the rotational populations of O-2 along supersonic jets of O-2 and He mixtures. The MEQ is expressed […]