Quantum dynamics study of the hydrogen molecule confined in singlewalled carbon nanotubes

In the present work a full-dimensional study of the dynamics of a hydrogen molecule confined in a narrow Single-walled Carbon Nanotube (SWCNT) is performed by using the Multi-configurational Time-dependent Hartree approach. New insights on the coupling between the different degrees of freedom of the molecule during the diffusion along the nanotube are found and discussed

Quantum dynamics study of the hydrogen molecule confined in singlewalled carbon nanotubes

In the present work a full-dimensional study of the dynamics of a hydrogen molecule confined in a narrow Single-walled Carbon Nanotube (SWCNT) is performed by using the Multi-configurational Time-dependent Hartree approach. New insights on the coupling between the different degrees of freedom of the molecule during the diffusion along the nanotube are found and discussed

5D quantum dynamics of the H2@SWNT system: Quantitative study of the rotational-translational coupling

The dynamics of the dihydrogen molecule when confined in carbon nanotubes with different chiral- ities and diameters are studied by using a 5 dimensional model considering the most relevant degrees of freedom of the system. The nuclear eigenstates are calculated for an (8,0) and a (5,0) carbon nanotubes by the State-Average Multiconfigurational Time-dependent Hartree, and then studied using qualitative tools (mapping of the total wave functions onto given subspaces) and more rigorous analysis (different kinds of overlaps with reference functions). The qualitative analysis is seen to fail due to a strong coupling between the internal and translational degrees of freedom. Using more accurate tools allows us to gain a deeper insight into the behaviour of confined species

Adsorption of hydrogen molecules on carbon nanotubes using quantum chemistry and molecular dynamics

Physisorption and storage of molecular hydrogen on single-walled carbon nanotube (SWCNT) of various diameters and chiralities are studied by means of classical molecular dynamics (MD) simulations and a force field validated using DFT-D2 and CCSD(T) calculations. A nonrigid carbon nanotube model is implemented with stretching (C−C) and valence angle potentials (C− C−C) formulated as Morse and Harmonic cosine potentials, respectively. Our results evidence that the standard Lennard-Jones potential fails to describe the H2−H2 binding energies. Therefore, our simulations make use of a potential that contains two-body term with parameters obtained from fitting CCSD(T)/CBS binding energies. From our MD simulations, we have analyzed the interaction energies, radial distribution functions, gravimetric densities (% wt), and the distances of the adsorbed H2 layers to the three zigzag type of nanotubes (5,0), (10,0), and (15,0) at 100 and 300 K

Applicability of Sentinel-1 and Sentinel-2 images for the detection and delineation of crisis information in the scope of Copernicus EMS services

[EN] This study shows the inclusion of Sentinel-1 and Sentinel-2 images in the workflows to obtain of crisis information of different types of events and their applicability in the detection and monitoring of those events. Sentinel is an Earth Observation (EO) program that is currently being developed by the European Space Agency (ESA) in the scope of the Copernicus program operative since April 2012, formerly known as Global Monitoring for Environment and Security (GMES). This program comprises six missions, out of which three are active, Sentinel-1 that provides radar images, Sentinel-.2 providing High Resolution optical images and Sentinel-3 developed to support GMES ocean, land, atmospheric, emergency, security and cryospheric applications. The present paper describes the use of Sentinel-1 radar to detect and delineate flooded areas, and the MultiTemporal Coherence (MTC) analysis applied with pre and post-event images to delimit and monitor burnt areas and lava flows. With respect to Sentinel-2, its high spectral resolution bands allowed the delineation of burnt areas by calculating differences of vegetation and burnt indices using pre and postevent images. Results using Sentinel-1 and Sentinel-2 data were compared with results using higher spatial resolution images, both optical and radar. In all cases, the usability of Sentinel images was proven.[ES] El principal objetivo de este trabajo ha consistido en analizar la aplicabilidad de la incorporación de imágenes Sentinel-1 y Sentinel-2 en los flujos de trabajo para obtener información de crisis de diferente naturaleza, así como su aplicación en la detección y monitorización de dichos eventos. Sentinel es un programa de observación de la tierra que está siendo desarrollado por la Agencia Espacial Europea (ESA) en el marco del programa Copernicus operativo desde abril de 2012, previamente denominado Global Monitoring for Environment and Security (GMES). Consta de seis misiones, de las cuales en estos momentos están activas tres, Sentinel-1 que proporciona imágenes radar, Sentinel-2 que proporciona imágenes ópticas de Alta Resolución y Sentinel-3, que proporciona servicios globales de vigilancia terrestre, atmosférica, de gestión de emergencias y seguridad y de la criosfera. En el presente artículo, se muestra la aplicación práctica de los datos radar Sentinel-1 en la detección de zonas inundadas y su uso para la detección de cambios por medio de análisis MultiTemporal de Coherencia (MTC) de imágenes radar para la delimitación de incendios y monitorización de flujos de lava. Respecto a Sentinel-2, se explotan las capacidades que proporciona su alta resolución espectral para la delimitación de incendios mediante el cálculo de diferencias de índices de vegetación entre las imágenes pre- y post-evento. Los resultados usando Sentinel-1 y Sentinel-2 se han comparado, en todos los casos, con resultados obtenidos a partir de imágenes de mayor resolución espacial, tanto ópticas como radar. Los buenos resultados de estas comparaciones demuestran la utilidad de imágenes Sentinel para los 3 casos estudiados.Donezar-Hoyos, U.; Larrañaga Urien, A.; Tamés-Noriega, A.; Sánchez-Gil, C.; Albizua-Huarte, L.; Ciriza-Labiano, R.; Del Barrio-Arellano, F. (2017). Aplicación de imágenes Sentinel-1 y Sentinel-2 en la detección y delineación de información de crisis de desastres naturales en el marco de los servicios Copernicus EMS. Revista de Teledetección. (50):49-57. doi:10.4995/raet.2017.8896SWORD495750Altman, D.G. (1991). Practical statistics for medical research. New York. Chapman and Hall.Henry, J. ‐B., Chastanet, P., Fellah, K., & Desnos, Y. ‐L. (2006). Envisat multi‐polarized ASAR data for flood mapping. International Journal of Remote Sensing, 27(10), 1921-1929. doi:10.1080/0143116050048672

El Servicio de Validación de Copernicus EMS como vector de mejora de la cartografía de emergencias basada en Sentinel

[EN] The Copernicus Emergency Management Service (CEMS) is coordinated by the European Commission and “provides all actors involved in the management of natural disasters, man-made emergency situations, and humanitarian crises with timely and accurate geo-spatial information derived from satellite remote sensing and complemented by available in situ or open data sources”. It includes two components, Early Warning and Monitoring and Mapping. The latter provides on demand geo-spatial information derived from satellite imagery during all phases of the disaster management cycle. It includes 3 systems, Rapid Mapping (RM), Risk and Recovery Mapping (RRM), and a Validation Service. RM provides geospatial information immediately after a disaster to assess its impact; RRM in the prevention, preparation and reconstruction phases; and the Validation Service is in charge of validating and verifying the products generated by both, and of collecting and analyzing users’ feedback. The wide spectrum of activities framed in the Validation Service has allowed it to become a vector to improve the Mapping component through the testing of new methodologies, data input type, or approach for the creation of emergency cartography in the frame of the CEMS. The present paper introduces the main investigation lines based on Sentinel-1 and 2 for flood and fire monitoring that could be implemented in the CEMS services taking into consideration the characteristics of the Mapping component in terms of products to create and time constraints. The applicability of Sentinel-1 for flood monitoring based on the backscattering, the MultiTemporal Coherence (MTC), and dual polarization; and for burnt area delineation based on MTC was studied, while Sentinel-2 was used for burnt area delineation based on vegetation indices. Results indicate that proposed methodologies might be appropriate for the creation of crisis information products in large areas, due to the relative easy and fast implementation compared to classic photo interpretation, although further applicability analyses should be carried out.[ES] El Servicio de Gestión de Emergencias de Copernicus (CEMS), está coordinado por la Comisión Europea y “provee de información geoespacial precisa y oportuna derivada de la teledetección satelital y completada por fuentes de datos disponibles in situ o abiertas a todos los actores involucrados en la gestión de emergencias, bien sean derivadas de desastres naturales o producidos por el hombre, o de crisis humanitarias”. El servicio tiene dos componentes, uno de alerta temprana y monitoreo y otro de creación de mapas. El servicio de mapeo se encarga de proveer, bajo demanda, a los diferentes agentes de emergencias de información geoespacial derivada de imágenes de satélite en todas las fases de la gestión de emergencias, consta de 3 sistemas, Rapid Mapping (RM), Risk and Recovery Mapping (RRM), y Validation. RM aporta información inmediatamente después de un desastre para evaluar su impacto; RRM en las fases de prevención, preparación y reconstrucción; y la Validación se encarga de validar y verificar los productos generados por ambos, y de recoger y analizar los comentarios de los usuarios. El amplio espectro de actividades enmarcadas en él le ha permitido ser vector de mejora de los servicios de mapeo de emergencias mediante el testeo de nuevas metodologías, tipos de datos, o enfoques para la creación de cartografías de emergencias en el marco de CEMS. El presente artículo describe las principales líneas de investigación en el uso de datos Sentinel-1 y 2 para la monitorización de inundaciones e incendios, que se podrían implementar en el futuro en el marco de CEMS. La aplicabilidad de Sentinel-1 para el monitoreo de inundaciones basado en la retrodispersión, la coherencia multitemporal (MTC) y la polarización dual; y se estudió la delimitación del área quemada basada en MTC. Sentinel-2 se usó para delimitar áreas quemadas en base a índices de vegetación. Los resultados indican que las metodologías propuestas podrían ser apropiadas para la creación de productos de información de crisis en grandes áreas, debido a la implementación relativamente fácil y rápida en comparación con la fotointerpretación clásica, aunque deberían realizarse más análisis para su aplicación en el marco de CEMS.The authors gratefully acknowledge the contribution of Massimiliano Rossi and Antigoni Maistrali for the preparation of the materials analysed in this work.Donezar-Hoyos, U.; Albizua-Huarte, L.; Amezketa-Lizarraga, E.; Barinagarrementeria-Arrese, I.; Ciriza, R.; De Blas-Corral, T.; Larrañaga-Urien, A.... (2020). The Copernicus EMS Validation service as a vector for improving the emergency mapping based on Sentinel data. Revista de Teledetección. 0(56):23-34. https://doi.org/10.4995/raet.2020.13770OJS233405

Conditional Born–Oppenheimer Dynamics: Quantum Dynamics Simulations for the Model Porphine

We report a new theoretical approach to solve adiabatic quantum molecular dynamics halfway between wave function and trajectory-based methods. The evolution of a N-body nuclear wave function moving on a 3N-dimensional Born–Oppenheimer potential-energy hyper-surface is rewritten in terms of single-nuclei wave functions evolving nonunitarily on a 3-dimensional potential-energy surface that depends parametrically on the configuration of an ensemble of generally defined trajectories. The scheme is exact and, together with the use of trajectory-based statistical techniques, can be exploited to circumvent the calculation and storage of many-body quantities (e.g., wave function and potential-energy surface) whose size scales exponentially with the number of nuclear degrees of freedom. As a proof of concept, we present numerical simulations of a 2-dimensional model porphine where switching from concerted to sequential double proton transfer (and back) is induced quantum mechanically

On the suitability of the ILJ function to match different formulations of the electrostatic potential for water-water interactions

Energetic and structural properties of liquid water have been calculated using molecular dynamics simulations in order to investigate the effect of different formulations of the van der Waals (vdW) interaction on the behaviour of liquid water. In particular, two model potentials, the SPC/E using a Lennard Jones (LJ) function and the AMPF using an Improved Lennard Jones function (ILJ) have been considered. The flexibility of the ILJ function in the AMPF model has also been analysed, proving that its vdW component can match different parametrizations of the electrostatic component.