Photodissociation of HCN and HNC isomers in the 7-10 eV energy range

13 págs.; 11 figs.; 1 tab.The ultraviolet photoabsorption spectra of the HCN and HNC isomers have been simulated in the 7-10 eV photon energy range. For this purpose, the three-dimensional adiabatic potential energy surfaces of the 7 lowest electronic states, and the corresponding transition dipole moments, have been calculated, at multireference configuration interaction level. The spectra are calculated with a quantum wave packet method on these adiabatic potential energy surfaces. The spectra for the 3 lower excited states, the dissociative electronic states, correspond essentially to predissociation peaks, most of them through tunneling on the same adiabatic state. The 3 higher electronic states are bound, hereafter electronic bound states, and their spectra consist of delta lines, in the adiabatic approximation. The radiative lifetime towards the ground electronic states of these bound states has been calculated, being longer than 10 ns in all cases, much longer that the characteristic predissociation lifetimes. The spectra of HCN is compared with the available experimental and previous theoretical simulations, while in the case of HNC there are no previous studies to our knowledge. The spectrum for HNC is considerably more intense than that of HCN in the 7-10 eV photon energy range, which points to a higher photodissociation rate for HNC, compared to HCN, in astrophysical environments illuminated by ultraviolet radiation. ©2016 AIP Publishing LLCThe research leading to these results has received funding from the European Research Council (ERC Grant No. 610256: NANOCOSMOS) and the Spanish Ministerio de Economía y Competividad under Grant Nos. CSD2009-00038, AYA2009-07304, AYA2012-32032, and FIS2014-52172-C2.Peer Reviewe

Zero-energy pinning from interactions in Majorana nanowires

Majorana zero modes at the boundaries of topological superconductors are charge-neutral, an equal superposition of electrons and holes. This ideal situation is, however, hard to achieve in physical implementations, such as proximitized semiconducting nanowires of realistic length. In such systems Majorana overlaps are unavoidable and lead to their hybridization into charged Bogoliubov quasiparticles of finite energy, which, unlike true zero modes, are affected by electronic interactions. We here demonstrate that these interactions, particularly with bound charges in the dielectric surroundings, drastically change the non-interacting paradigm. Remarkably, interactions may completely suppress Majorana hybridization around parity crossings, where the total charge in the nanowire changes. This effect, dubbed zero-energy pinning, stabilizes Majoranas back to zero energy and charge, and leads to electronically incompressible parameter regions wherein Majoranas remain insensitive to local perturbations, despite their overlapWe thank K. Flensberg for illuminating discussions. We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness through the Ramón y Cajal program RYC-2013-14645 and RYC-2011-09345, grant Nos. FIS2012-33521, FIS2013-47328-C2-1-P, FIS2014-55486-P, FIS2015-65706-P, FIS2015-64654-P (MINECO/FEDER), and the “María de Maeztu” Program for Units of Excellence in R&D (MDM-2014-0377

State-to-state reaction probabilities using bond coordinates: application to the Li+HF(v,j) collision

A time-dependent method to evaluate state-to-state reaction probabilities is presented. For demonstration purposes, the method is applied to Li+HF(v=0, 1, j=0, J=0) reactive collisions using the global potential energy surfaces (GPES). This accuracy of the method is very good when compared with recent time-independent hyperspherical calculations in this system.This work has been supported by DGICYT (Ministerio de Educación y Ciencia, Spain) under Grant Nos. PB97-0027 and PB95-0071, and by the European TMR network Contract No. ERBFMRXCT96-0088. M. L. also thanks the Comunidad Autónoma de Madrid for a Grant. We also want to acknowledge DGICYT and CIEMAT for the use of a CRAY-J90.Peer Reviewe

Depolarizing collisions with hydrogen: neutral and singly ionized alkaline earths

Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkaly-earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H. We compute ab initio potential curves of the atom-H system and solve the quantum mechanical dynamics. From the scattering amplitudes we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T <10000 K. A comparative analysis of our results and previous calculations in the literature is done. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali-earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.Comment: 18 pages, 3 figures. Summitted to ApJ (2014

Procedimiento administrativo de cese colectivo por motivos económicos: una visión crítica

En el presente estudio nos aproximamos al Procedimiento administrativo de cese colectivo por motivos económicos a partir de una visión crítica de dicho procedimiento, el mismo que, a nuestro entender, adolece de garantías propias del derecho administrativo. Así, el estudio plantea como objetivo brindar alternativas de solución al curso del procedimiento antes señalado, a fin de brindar contenido y respeto a los derechos de los trabajadores que pudieran ser afectados al término del procedimiento, evitando así el tener que acudir a la judicatura para salvaguardar dichos derechos. En ese sentido, resulta vital que se desarrollen mecanismos jurídicos que permitan a los administrados (en este caso, a los empleadores), obtener un pronunciamiento por parte de la Autoridad Administrativa de Trabajo que les genere la seguridad jurídica necesaria a partir de claridad en el mismo procedimiento. Por ello, resulta esencial recurrir a los principios del derecho administrativo a fin de que ilumine el procedimiento administrativo de cese colectivo por motivos económicos, pues el resultado de este va a repercutir no sólo en los empleadores sino, sobre todo, en los trabajadores. De esta manera, precisar plazos, otorgar contenido a lo requerido por la Autoridad Administrativa de Trabajo, y exigir un cabal cumplimiento de los pasos del procedimiento administrativo, nos permitirá tener las reglas claras en un escenario particularmente complejo como lo es la estabilidad laboral ante la inminente quiebra de una empresa.Trabajo académic

The lowest triplet state 3A′ of H3 +: Global potential energy surface and vibrational calculations

The adiabatic global potential energy surface of the H3 + system for the lowest triplet excited state of A ' symmetry was computed for an extensive grid of conformations around the minimum region at full configuration interaction ab initia level, using a much more extended basis set than in a previous paper from the same authors. An accurate global fit (rms error lower than 27 cm-1 for energies lower than dissociation into separated atoms and lower than 5 cm-1 for energies lower than the dissociation channel) to these ab initio points and also to part of the previous.calculated points (for a total of 7689 energies in the data set) of the lowest triplet excited state of A′ symmetry is obtained using a diatomics-in-molecules approach corrected by one symmetrized three-body term with a total of 109 linear parameters and 1 nonlinear parameter. This produces an accurate global potential which represents all aspects of the bound triplet excited state of H3 + including the minima and dissociation limits, satisfying the correct symmetry properties of the system. The vibrational eigenstates have been calculated using hyperspherical coordinates with symmetry adapted basis functions with the proper regular behavior at the Eckart singularities. .The accuracy of: the vibrational levels thus obtained is expected to be better than 2 cm-1 with respect to unknown experimental values. Due to the presence of three equivalent minima at collinear geometries (D∝h) the lower vibrational levels are close to triple degenerate. Since the .interconversion barrier between the three minima is about 2640 cm-1, these states split for the upper excited vibrational levels. Such splitting can provide a key feature to identifying the unassigned transitions amongst the many H3 + lines that have been observed in hydrogen plasmas. © 2007 American Institute of Physics.This work has been supported by DGICYT (Ministerio de Educación y Ciencia, Spain) under Grant Nos. PB97-0027 and PB95-0071.Peer Reviewe

Spin-orbit transitions in the N+^+(3PJA^3P_{J_A}) + H2_2 →\rightarrow NH+^+(X2ΠX^2\Pi, 4Σ−^4\Sigma^-)+ H(2S^2S) reaction, using adiabatic and mixed quantum-adiabatic statistical approaches

The cross section and rate constants for the title reaction are calculated for all the spin-orbit states of N$^+$($^3P_{J_A}$) using two statistical approaches, one purely adiabatic and the other one mixing quantum capture for the entrance channel and adiabatic treatment for the products channel. This is made by using a symmetry adapted basis set combining electronic (spin and orbital) and nuclear angular momenta in the reactants channel. To this aim, accurate {\it ab initio} calculations are performed separately for reactants and products. In the reactants channel, the three lowest electronic states (without spin-orbit couplings) have been diabatized, and the spin-orbit couplings have been introduced through a model localizing the spin-orbit interactions in the N$^+$ atom, which yields accurate results as compared to {\it ab initio} calculations including spin-orbit couplings. For the products, eleven purely adiabatic spin-orbit states have been determined with {\it ab initio} calculations. The reactive rate constants thus obtained are in very good agreement with the available experimental data for several ortho-H$_2$ fractions, assuming a thermal initial distribution of spin-orbit states. The rate constants for selected spin-orbit $J_A$ states are obtained, to provide a proper validation of the spin-orbit effects to obtain the experimental rate constants.Comment: 14 pages, 10 figures, submitted to J. Chem. Phy

L’esport com a mitjà per al foment de l’esportivitat: un programa educatiu en centres escolars alabesos

Aquest article presenta una experiència de treball continu, durant el curs acadèmic 2009-2010, per al foment de l’esportivitat i la prevenció de la violència en l’esport en edat escolar, inclosa en el programa d’esport escolar de la Diputació Foral d’Àlaba. Hi han participat els agents directes (entrenadors, pares i mares, joves esportistes i àrbitres) i indirectes (responsables institucionals, esportistes d’elit i mitjans de comunicació) que envolten els joves esportistes de 10 centres escolars de la província d’Àlaba. S’han implementat tres estratègies –1) “gest esportiu”; 2) tallers formatius, i 3) activitat del “world café”–, amb l’objectiu de reduir la incidència de comportaments antiesportius en els contextos esportius en edat escolar, fomentant subsegüentment els comportaments d’esportivitat. Els resultats mostren que els participants consideren que cadascuna de les accions implementades són útils per millorar la qualitat esportiva en els contextos esportius escolars

Communication: theoretical exploration of Au+H2, D2, and HD reactive collisions

The following article appeared in Journal of Chemical Physic 135.9 (2011): 091102 and may be found at http://scitation.aip.org/content/aip/journal/jcp/135/9/10.1063/1.3635772A quasi-classical study of the endoergic Au(1S)+ H2(X1Σg+) → AuHAuH+(2Σ+)+H(2S) reaction, and isotopic variants, is performed to compare with recent experimental results [F. Li, C. S. Hinton, M. Citir, F. Liu, and P. B. Armentrout, J. Chem. Phys. 134, 024310 (2011)]. For this purpose, a new global potential energy surface has been developed based on multi-reference configuration interaction ab initio calculations. The quasi-classical trajectory results show a very good agreement with the experiments, showing the same trends for the different isotopic variants of the hydrogen molecule. It is also found that the total dissociation into three fragments, Au+H+H, is the dominant reaction channel for energies above the H2 dissociation energy. This results from a well in the entrance channel of the potential energy surface, which enhances the probability of H-Au-H insertionA.D.-U. acknowledges a JAE fellowship supported by CSIC. This work is supported by Comunidad Autónoma de Madrid, Grant No. S2009/MAT/1467, and by Ministerio de Ciencia e Innovación, Grant Nos. CSD2009-00038 and FIS2010-18132. The calculations have been performed at CESGA and IFF computing centers. P.B.A. thanks the National Science Foundation for suppor