A transferable classical force field to describe glyme based lithium solvate ionic liquids.

A non-polarizable force field for lithium (Li+) and bis(trifluoromethanesulfonyl)imide (TFSI-) ions solvated in diglyme at around 0.2 mol fraction salt concentration was developed based on ab initio molecular dynamics (AIMD) simulations and a modified polymer consistent force field model. A force-torque matching based scheme, in conjunction with a genetic algorithm, was used to determine the Lennard-Jones (LJ) parameters of the ion-ion and ion-solvent interactions.

Probing the Electrode-Electrolyte Interface of Sodium/Glyme-Based Battery Electrolytes.

Sodium-ion batteries (NIBs) are promising systems for large-scale energy storage solutions; yet, further enhancements are required for their commercial viability. Improving the electrochemical performance of NIBs goes beyond the chemical description of the electrolyte and electrode materials as it requires a comprehensive understanding of the underlying mechanisms that govern the interface between electrodes and electrolytes. In particular, the decomposition reactions occurring at these interfaces lead to the formation of surface films.

Computational Energy Spectra of the H O@C Endofullerene.

A water molecule confined inside the C fullerene was quantum-mechanically described using a computational approach within the MCTDH framework. Such procedure involves the development of a full-dimensional coupled hamiltonian, with an exact kinetic energy operator, including all rotational, translational and vibrational degrees of freedom of the endofullerene system. In turn, through an effective pairwise potential model, the ground and rotationally excited states of the encapsulated H O inside the C cage were calculated, and traced back to the isotropic case of the H O@C endofullerene in order to understand the nature and physical origin of the symmetry breaking observed experimentally in the latter system.

Unraveling the Origin of Symmetry Breaking in H O@C Endofullerene Through Quantum Computations.

We explore the origin of the anomalous splitting of the 1 levels reported experimentally for the H O@C endofullerene, in order to give some insight about the physical interpretations of the symmetry breaking observed. We performed fully-coupled quantum computations within the multiconfiguration time-dependent Hartree approach employing a rigorous procedure to handle such computationally challenging problems. We introduce two competing physical models, and discuss the observed unconventional quantum patterns in terms of anisotropy in the interfullerene interactions, caused by the change in the off-center position of the encapsulated water molecules inside the cage or the uniaxial C -cage distortion, arising from noncovalent bonding upon water's encapsulation, or exohedral fullerene perturbations.

Encapsulation of a Water Molecule inside C Fullerene: The Impact of Confinement on Quantum Features.

We introduce an efficient quantum fully coupled computational scheme within the multiconfiguration time-dependent Hartree (MCTDH) approach to handle the otherwise extremely costly computations of translational-rotational-vibrational states and energies of light-molecule endofullenes. Quantum calculations on energy levels are reported for a water molecule inside C fullerene by means of such a systematic approach that includes all nine degrees of freedom of HO@C and does not consider restrictions above them. The potential energy operator is represented as a sum of natural potentials employing the -mode expansion, along with the exact kinetic energy operator, by introducing a set of Radau internal coordinates for the HO molecule.

Fully Coupled Quantum Treatment of Nanoconfined Systems: A Water Molecule inside a Fullerene C.

We implemented a systematic procedure for treating the quantal rotations by including all translational and vibrational degrees of freedom for any triatomic bent molecule in any embedded or confined environment, within the MCTDH framework. Fully coupled quantum treatments were employed to investigate unconventional properties in nanoconfined molecular systems. In this way, we facilitate a complete theoretical analysis of the underlying dynamics that enables us to compute the energy levels and the nuclear spin isomers of a single water molecule trapped in a C fullerene cage.

Temperature Dependence of HeBr Isomers' Stability through Rovibrational Multiconfiguration Time-Dependent Hartree Calculations.

The multiconfiguration time-dependent Hartree (MCTDH) method using a six-dimensional Hamiltonian that includes all rotational and vibrational degrees of freedom and an ab initio potential energy surface was employed to calculate the rovibronic states of the HeBr van der Waals complex. All rotational states of energies within 7 cm with respect to the energy of the linear ground state were calculated without restriction of the total angular momentum. In total, we obtained 500 and 320 rotationally excited states of the ground vibrational T-shaped and linear isomers of the HeBr, respectively, and compared them with those predicted by the rigid rotor model.