MiMiC: A high-performance framework for multiscale molecular dynamics simulations.

MiMiC is a framework for performing multiscale simulations in which loosely coupled external programs describe individual subsystems at different resolutions and levels of theory. To make it highly efficient and flexible, we adopt an interoperable approach based on a multiple-program multiple-data (MPMD) paradigm, serving as an intermediary responsible for fast data exchange and interactions between the subsystems. The main goal of MiMiC is to avoid interfering with the underlying parallelization of the external programs, including the operability on hybrid architectures (e.

Electron-vibrational renormalization in fullerenes through and machine learning methods.

The effect of nuclear vibrations on the electronic eigenvalues and the HOMO-LUMO gap is known for several kinds of carbon-based materials, like diamond, diamondoids, carbon nanoclusters, carbon nanotubes and others, like hydrogen-terminated oligoynes and polyyne. However, it has not been widely analysed in another remarkable kind which presents both theoretical and technological interest: fullerenes. In this article we present the study of the HOMO, LUMO and gap renormalizations due to zero-point motion of a relatively large number (163) of fullerenes and fullerene derivatives.

Multiscale biomolecular simulations in the exascale era.

The complexity of biological systems and processes, spanning molecular to macroscopic scales, necessitates the use of multiscale simulations to get a comprehensive understanding. Quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations are crucial for capturing processes beyond the reach of classical MD simulations. The advent of exascale computing offers unprecedented opportunities for scientific exploration, not least within life sciences, where simulations are essential to unravel intricate molecular mechanisms underlying biological processes.

Polarizable Embedding Potentials through Molecular Fractionation with Conjugate Caps Including Hydrogen Bonds.

Polarizable embedding (PE) refers to classical embedding approaches, such as those used in quantum mechanics/molecular mechanics (QM/MM), that allow mutual polarization between the quantum and classical regions. The quality of the embedding potential is critical to provide accurate results, e.g.

Polarizable Embedding without Artificial Boundary Polarization.

We present a fully self-consistent polarizable embedding (PE) model that does not suffer from unphysical boundary polarization. This is achieved through the use of the minimum-image convention (MIC) in the induced electrostatics. It is a simple yet effective approach that includes a more physically accurate description of the polarization throughout the molecular system.

Red Shift in Optical Excitations on Layered Copper Perovskites under Pressure: Role of the Orthorhombic Instability.

The red shift under pressure in optical transitions of layered compounds with CuCl units is explored through first-principles calculations and the analysis of available experimental data. The results on Cu -doped (C H NH ) CdCl , that is taken as a guide, show the existence of a highly anisotropic response to pressure related to a structural instability, driven by a negative force constant, that leads to an orthorhombic geometry of CuCl units but with a hole displaying a dominant 3z -r character (z being the direction perpendicular to the layer plane). As a result of such an instability, a pressure of only 3 GPa reduces by 0.

Pressure Effects on 3d (n=4, 9) Insulating Compounds: Long Axis Switch in Na MnF not Due to the Jahn-Teller Effect.

The pressure-induced switch of the long axis of MnF units in the monoclinic Na MnF compound and Mn -doped Na FeF is explored with the help of first principles calculations. Although the switch phenomenon is usually related to the Jahn-Teller effect, we show that, due to symmetry reasons, it cannot take place in 3d (n=4, 9) systems displaying a static Jahn-Teller effect. By contrast, we prove that in Na MnF the switch arises from the anisotropic response of the low symmetry lattice to hydrostatic pressure.

Element-specific investigations of ultrafast dynamics in photoexcited CuZnSnS nanoparticles in solution.

Ultrafast, light-induced dynamics in copper-zinc-tin-sulfide (CZTS) photovoltaic nanoparticles are investigated through a combination of optical and x-ray transient absorption spectroscopy. Laser-pump, x-ray-probe spectroscopy on a colloidal CZTS nanoparticle ink yields element-specificity, which reveals a rapid photo-induced shift of electron density away from Cu-sites, affecting the molecular orbital occupation and structure of CZTS. We observe the formation of a stable charge-separated and thermally excited structure, which persists for nanoseconds and involves an increased charge density at the Zn sites.

Ab initio Molecular Dynamics Investigations of the Speciation and Reactivity of Deep Eutectic Electrolytes in Aluminum Batteries.

Invited for this month's cover is the Section for Atomic Scale Materials Modelling led by Prof. Tejs Vegge at the Department of Energy Conversion and Storage, Technical University of Denmark. The central image of the cover picture illustrates one of the chemical reaction mechanisms observed in a deep eutectic electrolyte formed by AlCl and urea.

Ab initio Molecular Dynamics Investigations of the Speciation and Reactivity of Deep Eutectic Electrolytes in Aluminum Batteries.

Deep eutectic solvents (DESs) have emerged as an alternative for conventional ionic liquids in aluminum batteries. Elucidating DESs composition is fundamental to understand aluminum electrodeposition in the battery anode. Despite numerous experimental efforts, the speciation of these DESs remains elusive.

Understanding the Molecular Structure of the Elastic and Thermoreversible AlCl : Urea/Polyethylene Oxide Gel Electrolyte.

It is possible to prepare elastic and thermoreversible gel electrolytes with significant electroactivity by dissolving minimal weight fractions of ultra-high molecular weight polyethylene oxide (UHMW PEO) in an aluminum deep eutectic solvent (DES) electrolyte composed of AlCl and urea at a molar ratio of 1.5 : 1 (AlCl /urea). The experimental vibrational spectra (FTIR and Raman) provide valuable information on the structure and composition of the gel electrolyte.