An ab initio multiconfigurational description of core hole and shake up excited states in small molecules

In this contribution, equilibrium geometries and potential energy curves computed at the CASSCF level of theory for the core hole and shake up superexcited states of small size molecules will be presented. The effect of dynamic correlation on the description of these species will be discussed based on preliminary multireference configuration interaction energetic

Fate of 15N-fertilizers in the soil-plant system of a forage rotation under conservation and plough tillage.

The long-term effect of conventional plough tillage (PT) and conservation minimum tillage (MT) on soil N (0-5, 5-15, 15-30, 30-45 and 45-60 cm), recovery efficiency of 15N-fertilizer (REN), plant N concentration and N exported with crops was evaluated during two years in a 14-year-old ryegrass-maize forage rotation. Adjacent PT (n=9) and MT (n=9) plots were randomly assigned in triplicate to three treatments to which 15NH4 15NO3 (10 atom % 15N) was applied in one of the three first fertilizations (15NOctober-, 15NMarch- and 15NMay-fertilizer), the others being done with unlabelled N. Plant N concentration (% N) was affected (p ryegrass-2 (1.9 ± 0.4%) > maize-2 (1.4 ± 0.1 %) > maize-1 (1.1 ± 0.2 %)] and the crop-tillage interaction (22 % of variance explained). Jointly considering all data, more 15N-fertilizer was recovered in the MT (25 ± 4 %) than in the PT soil profile (19 ± 6 %) at the end of the experiment whereas the N exported with the crops was unaffected by the tillage system and varied from 5-6 % (15NOctober-fertilizer) to 45-49% (15NMarchfertilizer) and 52-53 % (15NMay-fertilizer; despite only three instead of four subsequent crops were studied).The 15N unaccounted for in the case of 15NOctober-fertilizer (72 ± 5 %) was more than twice that in 15NMarch- (34 ± 7 %) and 15NMay-fertilizer (25 ± 14 %). Considering soil, site and weather conditions, denitrification and nitrate leaching during the ryegrass-1 crop were the most likely processes explaining the high losses of the 15NOctober-fertilizer. Results suggested a higher initial immobilization of the applied 15N in the soil organic matter (SOM) of MT, that reduces 15N availability to the first crop, followed by an increase of the residual availability of the fertilizer 15N to the subsequent 2-3 crops.Peer reviewe

Let the trajectories tell a quantum story: Post-entangling the SHARC scheme

A new method is proposed to perform Quantum Wave Packet Nuclear Dynamics on large systems, by making use of information obtained by Semi-Classical Quantum Dynamics. The key of the method resides in expressing the nuclear wave function of the system in a basis set determined by the positions of multiple trajectories at each tim

Molecular-frame photoelectron angular distributions of CO in the vicinity of feshbach resonances: an xchem approach

The advent of ultrashort XUV pulses is pushing for the development of accurate theoretical calculations to describe ionization of molecules in regions where electron correlation plays a significant role. Here, we present an extension of the XCHEM methodology to evaluate laboratory- and molecular-frame photoelectron angular distributions in the region where Feshbach resonances are expected to appear. The performance of the method is demonstrated in the CO molecule, for which information on Feshbach resonances is very scarce. We show that photoelectron angular distributions are dramatically affected by the presence of resonances, to the point that they can completely reverse the preferred electron emission direction observed in direct nonresonant photoionization. This is the consequence of significant changes in the electronic structure of the molecule when resonances decay, an effect that is mostly driven by electron correlation in the ionization continuum. The present methodology can thus be helpful for the interpretation of angularly resolved photoionization time delays in this and more complex moleculesThe work was supported by the European COST Action AttoChem (CA18222) and the Spanish State Research Agency (AEI/ 10.13039/501100011033), Grants PID2019-105458RB-I00 and PID2019-106732GB-I00, “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2016-0686) and “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000805-M

Electron correlation in the ionization continuum of molecules: Photoionization of N2 in the vicinity of the Hopfield series of autoionizing states

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry Letters, copyright © 2018 American Chemical Society after peer review. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpclett.7b03220Direct measurement of autoionization lifetimes by using time-resolved experimental techniques is a promising approach when energy-resolved spectroscopic methods do not work. Attosecond time-resolved experiments have recently provided the first quantitative determination of autoionization lifetimes of the lowest members of the well-known Hopfield series of resonances in N2. In this work, we have used the recently developed XCHEM approach to study photoionization of the N2molecule in the vicinity of these resonances. The XCHEM approach allows us to describe electron correlation in the molecular electronic continuum at a level similar to that provided by multireference configuration interaction methods in bound state calculations, a necessary condition to accurately describe autoionization, shakeup, and interchannel couplings occurring in this range of photon energies. Our results show that electron correlation leading to interchannel mixing is the main factor that determines the magnitude and shape of the N2photoionization cross sections, as well as the lifetimes of the Hopfield resonances. At variance with recent speculations, nonadiabatic effects do not seem to play a significant role. These conclusions are supported by the very good agreement between the calculated cross sections and those determined in synchrotron radiation and attosecond experimentsThis work has been supported by the ERC advanced grant 290853 - XCHEM - within the seventh framework programme of the European Union, the ERC proof-of-concept grant 780284 - Imaging-XChem - within the Horizon2020 Framework Programme, and the MINECO projects FIS2013-42002-R and FIS2016-77889-R (AEI/FEDER, UE). We also acknowledge computer time from CCC-UAM and Marenostrum Supercomputer Centers. L.A. acknowledges support from the TAMOP NSF Grant No. 1607588, as well as UCF fundin

Partial cross sections and interfering resonances in photoionization of molecular nitrogen

We present an in-depth theoretical study of N2 photoionization in the region between the second (2Πu) and third (2Σu+) ionization thresholds. In this region, the electronic continuum includes the Hopfield series of autoionizing states, corresponding to excitations to nsσd, ndσd, and ndπg molecular orbitals. Calculations have been performed by using the xchem code, which makes use of a Gaussian and B-spline hybrid basis in the framework of a close-coupling approach. We provide total and partial photoionization cross sections for all open channels, energy positions, and widths for the five lowest resonances of each series and, when resonances are well isolated from each other, Fano and Starace parameters. We also discuss how the coupling between the two series of overlapping resonances, nsσd and ndσd, affects their energies and autoionization widths. These results show the potential of the xchem method to describe resonant photoionization in moleculesThis work has been supported by the ERC Advanced Grant No. 290853 – XCHEM – within the Seventh Framework Program of the European Union, the ERC Proof-of-Concept Grant No. 780284 – Imaging-XChem – within the Horizon 2020 Framework Programme, and MINECO Project No. FIS2016-77889-R (AEI/FEDER, UE). L.A. acknowledges support from the TAMOP NSF through Grant No. 1607588, as well as UCF fundin

Las II Jornadas de Jóvenes Investigadores en Proteómica, en Córdoba 2010

Comunicaciones a congreso

Balance de las II Jornadas Bienales de Jóvenes Investigadores en Proteómica, Córdoba 2010

Comunicaciones a congreso