### 2024

# Assessing the feasibility of Na_{6}MgCl_{8} as a material for all-solid-state sodium ion batteries: A theoretical approach

## The search of outstanding materials used in sodium-ion batteries has to solve the two main challenges concerning the interfacial resistance between the solid-state electrolyte with the electrodes and relative high dc-conductivity at operative temperatures. In this work advanced atomistic simulations are used to evaluate the main properties of Na_{6}MgCl_{8} rocksalt structure as a battery material for Na-ion Batteries. The results show that Na_{6}MgCl_{8} has an insulating characteristic with an energy gap of ∼5.1 eV and is mechanically stable, ductile, and compatible with many possible electrodes/electrolytes. The simulations also predict that Zn^{2+} is the best divalent dopant, improving the defect characteristics and transport properties of Na_{6}MgCl_{8}. Large-scale molecular dynamics simulations show that Ba^{2+} and Zn^{2+} doping improve the Na ion transport, with a predicted Na conductivity of ∼10^{−7} Scm^{−1} at room temperature. Overall, these results suggest that Na_{6}MgCl_{8} can be considered as a promising material for use in Na-ion batteries and further experimental confirmation is needed to verify these predictions.

# A theoretical study of the Li_{5}B_{3}Si_{x}(BH)_{3-x} isolobal systems with x = 0–3: Remarkable materials for H_{2} adsorption

In this study we investigate the stability of the isomers of the Li_{n}B_{3}Si_{3} clusters with n = 0–7 using both density functional theory and coupled-cluster theory CCSD(T) calculations using both the def2-TZVPP and def2-QZVPP basis sets and the total energy is subsequently extrapolated to the complete basis set limit (CBS). Calculated results reveal closely spaced energies among the four most stable isomers for each size, except for n = 5. The Li_{5}B_{3}Si_{3} isomers exhibit significant energy gaps, and a high thermodynamic stability as suggested by ΔE and Δ_{2}E values for its lowest-energy isomer. Of particular importance, Li_{5}B_{3}Si_{3} emerges as a material able to capture a large amount of molecular hydrogen. To enhance the wt%, a substitution of Si atom by a BH unit tends to yield stabilized compounds Li_{5}B_{3}Si_{2}(BH), Li_{5}B_{3}Si(BH)_{2} and Li_{5}B_{3}(BH)_{3}. Molecular dynamics simulations (BOMD) at up to 1200K confirm their thermal stability. Magnetic ring current maps identify them as doubly aromatic species, explaining their high stability. Each of these four Li_{5} compounds can adsorb up to 24H_{2} molecules with adsorption energies of 0.1–0.2 eV. The Li_{5}B_{3}(BH)_{3} shows the most favorable wt% improvement as compared to the previously known B_{12}Li_{8} cluster. A survey shows that all clusters can adsorb 24H_{2} at pressures up to 100 atm and temperatures below 80 K, fitting the effective range for cryo-compressed hydrogen storage.

# The Jarzynski binding free energy can effectively rank ligand-protein affinities in inadequate samplings

The use of the Jarzynski equality for estimating ligand–protein binding free energies are illustrated for cases of inadequate samplings. Data obtained from a large amount (10^{4}) of work are thus converged to an incorrect value, due to creation of a distorted Gaussian-like distribution. However, even in such cases, the Jarzynski equality can effectively rank binding affinities in the early stage of rational drug design. A combination of steered molecular dynamics calculations, Jarzynski relation and block averaging can provide such relative binding free energies having significantly better correlations in the cases of the thrombin and HIV-1 complexes examined.

### 2022

https://pubs.rsc.org/en/content/articlelanding/2022/RA/D1RA08527A

A theoretical study of geometric and electronic structures, stability and magnetic properties of both neutral and anionic Ge_{16}M^{0/−} clusters with M being a first-row 3d transition metal atom, is performed using quantum chemical approaches. Both the isoelectronic Ge_{16}Sc^{−} anion and neutral Ge_{16}Ti that have a perfect Frank–Kasper tetrahedral *T*_{d} shape and an electron shell filled with 68 valence electrons, emerge as magic clusters with an enhanced thermodynamic stability. The latter can be rationalized by the simple Jellium model. Geometric distortions from the Frank–Kasper tetrahedron of Ge_{16}M having more or less than 68 valence electrons can be understood by a Jahn–Teller effect. Remarkably, DFT calculations reveal that both neutral Ge_{16}Sc and Ge_{16}Cu can be considered as superhalogens as their electron affinities (≥3.6 eV) exceed the value of the halogen atoms and even that of icosahedral Al_{13}. A detailed view of the magnetic behavior of Ge_{16}M^{0/−} clusters shows that the magnetic moments of the atomic metals remain large even when they are quenched upon doping. When M goes from Sc to Zn, the total spin magnetic moment of Ge_{16}M^{0/−} increases steadily and reaches the maximum value of 3 *μ*_{B} with M = Mn before decreasing towards the end of the first-row 3d block metals. Furthermore, the IR spectra of some tetrahedral Ge_{16}M are also predicted.