Borophene nanoclusters: Energetics and structures from analytical potentials.

Boron shows a variety of properties, determining a chemistry rich and complementary to that of carbon, the neighbor atom in the Periodic Table. In this work, we investigated the strength and nature of the interaction involving B12 or B36 monomer, which represent molecular prototypes of borophene, the two-dimensional allotrope of elemental boron. For the representation of the intermolecular interaction, we developed new potential energy surfaces (PESs) that are based on accurate ab initio or density functional theory data.

Sodium into γ-Graphyne Multilayers: An Intercalation Compound for Anodes in Metal-Ion Batteries.

The bulk synthesis of γ-graphyne has been recently achieved and evidenced a multilayered structure, which suggests its potential exploitation as a substitute of graphite-based anode materials for metals heavier than lithium (Li). In fact, each of its regular pores of sub-nanometric size features an optimal environment for hosting a single sodium (Na) ion, as reported here by means of accurate electronic structure calculations. We show that the graphyneNa ion coupling mimics that found on the grapheneLi ion in terms of metal-single layer interaction and equilibrium distance.

Separation of oxygen from nitrogen using a graphdiyne membrane: a quantum-mechanical study.

Efficient separation of oxygen and nitrogen from air is a process of great importance for many industrial and medical applications. Two-dimensional (2D) membranes are very promising materials for separation of gases, as they offer enhanced mass transport due to their smallest atomic thickness. In this work, we examine the capacity of graphdiyne (GDY), a new 2D carbon allotrope with regular subnanometric pores, for separating oxygen (O) from nitrogen (N).

Improved Quantum-Classical Treatment of N-N Inelastic Collisions: Effect of the Potentials and Complete Rate Coefficient Data Sets.

In this study, complete (, including all vibrational quantum numbers in an N vibrational ladder) data sets of vibration-to-vibration and vibration-to-translation rate coefficients for N-N collisions are explicitly computed along with transport properties (shear and bulk viscosity, thermal conductivity, and self-diffusion) in the temperature range 100-9000 K. To reach this goal, we improved a mixed quantum-classical (MQC) dynamics approach by lifting the constraint of a Morse treatment of the vibrational wave function and intramolecular potential and permitting the use of more realistic and flexible representations. The new formulation has also allowed us to separately analyze the role of intra- and intermolecular potentials on the calculated rates and properties.

Attachment of Hydrogen Molecules to Atomic Ions (Na , Cl ): Examination of an Adiabatic Separation of the H Rotational Motion.

Interactions between molecular hydrogen and ions are of interest in cluster science, astrochemistry and hydrogen storage. In dynamical simulations, H molecules are usually modelled as point particles, an approximation that can fail for anisotropic interactions. Here, we apply an adiabatic separation of the H rotational motion to build effective pseudoatom-ion potentials and in turn study the properties of (H ) Na /Cl clusters.

Correction: Helium nanodroplets as an efficient tool to investigate hydrogen attachment to alkali cations.

Correction for 'Helium nanodroplets as an efficient tool to investigate hydrogen attachment to alkali cations' by Siegfried Kollotzek , , 2023, , 462-470, https://doi.org/10.1039/D2CP03841B.

Graphene as Nanocarrier for Gold(I)-Monocarbene Complexes: Strength and Nature of Physisorption.

Gold(I) metal complexes are finding increasing applications as therapeutic agents against a variety of diseases. As their potential use as effective metallodrugs is continuously confirmed, the issue of their administration, distribution and delivery to desired biological targets emerges. Graphene and its derivatives possess attractive properties in terms of high affinity and low toxicity, suggesting that they can efficaciously be used as drug nanocarriers.

Observation of Multiple Ordered Solvation Shells in Doped Helium Droplets: The Case of HeCa.

In this Letter, we report the experimental detection of likely the largest ordered structure of helium atoms surrounding a monatomic impurity observed to date using a recently developed technique. The mass spectrometry investigation of HeCa clusters, formed in multiply charged helium nanodroplets, reveals magic numbers at = 12, 32, 44, and 74. Classical optimization and path integral Monte Carlo calculations suggest the existence of up to four shells surrounding the calcium dication which are closed with well-ordered Mozartkugel-like structures: HeCa with an icosahedron, the second at HeCa with a dodecahedron, the third at HeCa with a larger icosahedron, and finally for HeCa, we find that the outermost He atoms form an icosidodecahedron which contains the other inner shells.

Helium nanodroplets as an efficient tool to investigate hydrogen attachment to alkali cations.

We report a novel method to reversibly attach and detach hydrogen molecules to positively charged sodium clusters formed inside a helium nanodroplet host matrix. It is based on the controlled production of multiply charged helium droplets which, after picking up sodium atoms and exposure to H vapor, lead to the formation of Na(H) clusters, whose population was accurately measured using a time-of-flight mass spectrometer. The mass spectra reveal particularly favorable Na(H) and Na(H) clusters for specific "magic" numbers of attached hydrogen molecules.

Multilayer Graphtriyne Membranes for Separation and Storage of CO: Molecular Dynamics Simulations of Post-Combustion Model Mixtures.

The ability to remove carbon dioxide from gaseous mixtures is a necessary step toward the reduction of greenhouse gas emissions. As a contribution to this field of research, we performed a molecular dynamics study assessing the separation and adsorption properties of multi-layered graphtriyne membranes on gaseous mixtures of CO, N, and HO. These mixtures closely resemble post-combustion gaseous products and are, therefore, suitable prototypes with which to model possible technological applications in the field of CO removal methodologies.

Molecular hydrogen isotope separation by a graphdiyne membrane: a quantum-mechanical study.

Graphdiyne (GDY) has emerged as a very promising two-dimensional (2D) membrane for gas separation technologies. One of the most challenging goals is the separation of deuterium (D) and tritium (T) from a mixture with the most abundant hydrogen isotope, H, an achievement that would be of great value for a number of industrial and scientific applications. In this work we study the separation of hydrogen isotopes in their transport through a GDY membrane due to mass-dependent quantum effects that are enhanced by the confinement provided by its intrinsic sub-nanometric pores.

Helium structures around SF and SF: novel intermolecular potential and mass spectrometry experiments.

Helium clusters around the recently experimentally observed sulphur hexafluoride SF and sulphur pentafluoride SF ions are investigated using a combined experimental and theoretical effort. Mass spectrometry ion yields are obtained and the energetics and structure of the corresponding He-SF and He-SF clusters are analyzed using path integral molecular dynamics calculations as a function of , the number of He atoms, employing a new intermolecular potential describing the interaction between the dopant and the surrounding helium. The new force field is optimized on benchmark potential energy calculations and represented by improved Lennard-Jonnes analytical expressions.

Vibrational Energy Transfer in CO+N Collisions: A Database for V-V and V-T/R Quantum-Classical Rate Coefficients.

Knowledge of energy exchange rate constants in inelastic collisions is critically required for accurate characterization and simulation of several processes in gaseous environments, including planetary atmospheres, plasma, combustion, etc. Determination of these rate constants requires accurate potential energy surfaces (PESs) that describe in detail the full interaction region space and the use of collision dynamics methods capable of including the most relevant quantum effects. In this work, we produce an extensive collection of vibration-to-vibration (V-V) and vibration-to-translation/rotation (V-T/R) energy transfer rate coefficients for collisions between CO and N2 molecules using a mixed quantum-classical method and a recently introduced (A.

Ca Ions Solvated in Helium Clusters.

We present a combined experimental and theoretical investigation on Ca+ ions in helium droplets, HeNCa+. The clusters have been formed in the laboratory by means of electron-impact ionization of Ca-doped helium nanodroplets. Energies and structures of such complexes have been computed using various approaches such as path integral Monte Carlo, diffusion Monte Carlo and basin-hopping methods.

Reconciling experimental and theoretical vibrational deactivation in low-energy O + N collisions.

Molecular dynamics calculations of inelastic collisions of atomic oxygen with molecular nitrogen are known to show orders of magnitude discrepancies with experimental results in the range from room temperature to many thousands of degrees Kelvin. In this work, we have achieved an unprecedented quantitative agreement with experiments even at low temperature, by including a non-adiabatic treatment involving vibronic states on newly developed potential energy surfaces. This result paves the way for the calculation of accurate and detailed databases of vibrational energy exchange rates for this collisional system.

An unrestricted approach for the accurate calculation of the intermolecular potential of (O): Implications for the solid epsilon phase.

Oxygen in its elemental form shows a variety of magnetic properties in its condensed phases; in particular, the epsilon solid phase loses its magnetism. These phenomena reflect the nature of the intermolecular forces present in the solid and the changes that arise with variations in pressure and temperature. In this study, we use intermolecular potentials obtained with unrestricted ab initio methods to model the singlet state of the oxygen tetramer [(O)], which is the unit cell, consistent with the non-magnetic character of this phase.

Energy exchange rate coefficients from vibrational inelastic O(Σg-3) + O(Σg-3) collisions on a new spin-averaged potential energy surface.

A new spin-averaged potential energy surface (PES) for non-reactive O(Σg-3) + O(Σg-3) collisions is presented. The potential is formulated analytically according to the nature of the principal interaction components, with the main van der Waals contribution described through the improved Lennard-Jones model. All the parameters involved in the formulation, having a physical meaning, have been modulated in restricted variation ranges, exploiting a combined analysis of experimental and ab initio reference data.

Helium Isotopes Quantum Sieving through Graphtriyne Membranes.

We report accurate quantum calculations of the sieving of Helium atoms by two-dimensional (2D) graphtriyne layers with a new interaction potential. Thermal rate constants and permeances in an ample temperature range are computed and compared for both Helium isotopes. With a pore larger than graphdiyne, the most common member of the γ-graphyne family, it could be expected that the appearance of quantum effects were more limited.

Interaction and Reactivity of Cisplatin Physisorbed on Graphene Oxide Nano-Prototypes.

The physical adsorption of cisplatin (CP) on graphene oxide (GO) and reduced graphene oxide (rGO) is investigated at the DFT level of theory by exploiting suitable molecular prototypes representing the most probable adsorbing regions of GO and rGO nano-structures. The results show that the CP binding energy is enhanced with respect to that for the interaction with pristine graphene. This is due to the preferential adsorption of the drug in correspondence of the epoxy and hydroxy groups located on GO basal plane: an energy decomposition analysis of the corresponding binding energy reveals that the most attractive contribution comes from the electrostatic attraction between the -NH 3 ends of CP and the oxygen groups on (r)GO, which can be associated with hydrogen bonding effects.

An unrestricted approach for the accurate calculation of the interaction potentials of open-shell monomers: The case of O-O.

The properties of molecular oxygen including its condensed phases continue to be of great relevance for the scientific community. The richness and complexity of its associated properties stem from the fact that it is a very stable diradical. Its open-shell nature leads to low-lying multiplets with total electronic spin S = 0, 1, 2 in the case of the dimer, (O), and the accurate calculation of the intermolecular potentials represents a challenge to ab initio electronic structure methods.

Inelastic rate coefficients based on an improved potential energy surface for N + N collisions in a wide temperature range.

A modification in the potential energy surface (PES) for N-N interactions, reported in the literature [D. Cappelletti et al., Phys.

Complexes of Alkali Metal Cations and Molecular Hydrogen: Potential Energy Surfaces and Bound States.

Complexes between metal cations and molecular hydrogen are systems quite amenable for precise spectroscopic and theoretical studies, and at the same time, they are relevant for applications in hydrogen storage and astrochemistry. In this work, we report new intermolecular potential energy surfaces and rovibrational states calculations for complexes involving molecular hydrogen and alkaline metal cations, M-H (M = Na, K, Rb, Cs). The intermolecular potentials, formulated in an internally consistent way to emphasize differences in the properties of the systems, are represented by simple analytical expressions whose parameters have been optimized from comparison with accurate calculations.

Snowball formation for Cs solvation in molecular hydrogen and deuterium.

Interactions of atomic cations with molecular hydrogen are of interest for a wide range of applications in hydrogen technologies. These interactions are fairly strong despite being non-covalent, hence one can ask whether hydrogen molecules would form dense, solid-like, solvation shells around the ion (snowballs) or rather a more weakly bound compound. In this work, the interactions between Cs+ and H2 are studied both experimentally and computationally.

Full Dimensional Potential Energy Function and Calculation of State-Specific Properties of the CO+N Inelastic Processes Within an Open Molecular Science Cloud Perspective.

A full dimensional Potential Energy Surface (PES) of the CO + N system has been generated by extending an approach already reported in the literature and applied to N-N (Cappelletti et al., 2008), CO-CO (Bartolomei et al., 2012), and CO-N (Lombardi et al.

A combined experimental and theoretical investigation of Cs ions solvated in He clusters.

Solvation of Cs ions inside helium droplets has been investigated both experimentally and theoretically. On the one hand, mass spectra of doped helium clusters ionized with a crossed electron beam, HeCs, have been recorded for sizes up to N = 60. The analysis of the ratio between the observed peaks for each size N reveals evidences of the closure of the first solvation shell when 17 He atoms surround the alkali ion.