395 research outputs found
Simulation of nanosizing effects in the decomposition of Ca(BH4)2 through atomistic thin film models
Along strike preorogenic thickness variation and onlapping geometries control on thrust wedge evolution: insight from sandbox analogue modelling
Abstract: Thickness variation of sedimentary sequences is largely viewed as a controlling factor on the
evolution of orogenic wedges; among the different structural and stratigraphic features generating
thickness variation, we focused our analysis on the onlapping geometries, using laboratory sandbox
experiments. The aim was trying to describe how a common sedimentary configuration could influence
thrusts geometry and mode of accretion. Model results showed that onlapping geometries in pretectonic
sediments cause a great complexity, dominated by curvilinear thrusts, back thrust and out-ofsequence
thrusts. They also influence mode of accretion, generating diachronous thrusting along strike,
reactivation and under-thrusting alternating to simple piggy-back sequence. Our modeling results are
compared with natural examples from the Apennines, the southern Pyrenees, the Pindos (Greece) and
the West Spitsbergen (Greenland) fold and thrust belts, among many others, where strain localization
and diachronic thrusting affecting thrust propagation in correspondence to complex geometries both
in the pre-orogenic stratigraphy and in the upper crust
A Combined Periodic Density Functional and Incremental Wave-Function-Based Approach for the Dipersion-Accounting Time-Resolved Dynamics of 4He Nanodroplets on Surfaces: 4He/Graphene
Helium-mediated Synthesis, Soft-landing and Spectroscopy of Metal Nanoparticles on Surfaces,CSIC, Madrid, Spain, October 10-11, 2014A general strategy to calculate accurate He-surface interaction potentials is proposed [1]. It extends the dispersionless density functional (dlDF) approach by Pernal et al. [2] to adsorbatesurface interactions by including periodic boundary conditions [1b]. A scheme to parametrize the dispersion interaction is introducced by calculating two- and three-body dispersion terms at CCSD(T) level via the method of increments [3]. The performance of the composite approach is tested on the low-lying selective adsorption states of 4He/graphene [5]. Second, its capability to describe dispersionless correlation effects realistically is used to extract dispersion effects in time-dependent density functional simulations on the collision of 4He droplets with graphene [1b]. Dispersion effects play a key role in the fast spreading of the 4He nanodroplet [1b,6], the evaporation-like process of helium atoms, and the formation of solid-like helium structures. These characteristics are expected to be quite general and highly relevant to explain experimental measurements with the newly developed helium droplet mediated deposition technique [7].Peer Reviewe
Combining the Hybrid Functional Method with Dynamical Mean-Field Theory
We present a new method to compute the electronic structure of correlated
materials combining the hybrid functional method with the dynamical mean-field
theory. As a test example of the method we study cerium sesquioxide, a strongly
correlated Mott-band insulator. The hybrid functional part improves the
magnitude of the pd-band gap which is underestimated in the standard
approximations to density functional theory while the dynamical mean-field
theory part splits the 4f-electron spectra into a lower and an upper Hubbard
band.Comment: 5 pages, 2 figures, replaced with revised version, published in
Europhys. Let
Reversible, Opto-Mechanically Induced Spin-Switching in a Nanoribbon-Spiropyran Hybrid Material
It has recently been shown that electronic transport in zigzag graphene
nanoribbons becomes spin-polarized upon application of an electric field across
the nanoribbon width. However, the electric fields required to experimentally
induce this magnetic state are typically large and difficult to apply in
practice. Here, using both first-principles density functional theory (DFT) and
time-dependent DFT, we show that a new spiropyran-based, mechanochromic polymer
noncovalently deposited on a nanoribbon can collectively function as a dual
opto-mechanical switch for modulating its own spin-polarization. These
calculations demonstrate that upon mechanical stress or photoabsorption, the
spiropyran chromophore isomerizes from a closed-configuration ground-state to a
zwitterionic excited-state, resulting in a large change in dipole moment that
alters the electrostatic environment of the nanoribbon. We show that the
electronic spin-distribution in the nanoribbon-spiropyran hybrid material can
be reversibly modulated via noninvasive optical and mechanical stimuli without
the need for large external electric fields. Our results suggest that the
reversible spintronic properties inherent to the nanoribbon-spiropyran material
allow the possibility of using this hybrid structure as a resettable,
molecular-logic quantum sensor where opto-mechanical stimuli are used as inputs
and the spin-polarized current induced in the nanoribbon substrate is the
measured output.Comment: Accepted by Nanoscal
- …