Graphynes are novel two-dimensional carbon-based materials that have been proposed as molecular filters, especially for water purification technologies. We carry out first-principles electronic structure calculations at the MP2C level of theory to assess interaction between and graphyne, graphdiyne, graphtriyne pores. The computed penetration barriers suggest transport is unfeasible through graphyne while being unimpeded graphtriyne. For with a pore size almost matching water, low barrier...

Two-dimensional (2D) materials deriving from graphene, such as graphdiyne and 2D polyphenylene honeycomb (2DPPH), have been recently synthesized exhibit uniformly distributed subnanometer pores, a feature that can be exploited for gas filtration applications. Accurate first-principles electronic structure calculations are reported showing pores permit an almost unimpeded helium transport while it is much more difficult through the 2DPPH openings. Quantum dynamical simulations on reliable new...

Global potentials for the physisorption of rare-gas atoms on graphene and graphite, amenable a variety dynamics simulations, are reported. An atom–bond pairwise additive form potential is used, where interaction pairs, represented by proper analytical functions, constituted Rg atom (Rg = He, Ne, Ar, Kr) C–C bonds sheet(s). The parameters pair potential, derived from polarizability interacting partners, fine-tuned, exploiting calculations prototypical Rg–coronene system using high-level...

Quasibound states of the HOCO intermediate in reaction OH+CO→H+CO2 are studied by means stabilization method. A reduced-dimensionality model is used. The calculated resonance positions and lifetimes agree well with previous quantum scattering calculations. Most quasibound can be assigned approximately to a vibrational excitation higher frequency OH vibration different progressions HO–CO stretching mode. Some interesting mode-specific effects dynamics unimolecular decay predicted.

Electric multipole moments, static dipole polarizabilities, and dynamic dipole, quadrupole, mixed dipole-octupole polarizabilities of molecular oxygen nitrogen in their ground electronic states have been obtained by means high level multiconfigurational ab initio calculations. From these properties, we electrostatic, dispersion, induction coefficients for the long-range interactions O(2)-O(2) , N(2)-N(2) O(2)-N(2) dimers. Our data is a comprehensive consistent set that shows very good...

We propose a fast and non-destructive spectroscopic method for single molecular ions that implements quantum logic schemes between an atomic ion the of interest. Our proposal relies on hybrid coherent manipulation two-ion system, using optical or magnetic forces depending types levels to be addressed (Zeeman, rotational, vibrational electronic degrees freedom). The is especially suited precision spectroscopy ions, sets starting point new computation combine covering measurement entangling steps.

Recent progress in the production of new two-dimensional (2D) nanoporous materials is attracting considerable interest for applications to isotope separation gases. In this paper we report a computational study transmission (4)He and (3)He through (subnanometer) pores graphdiyne, recently synthesized 2D carbon material. The He-graphdiyne interaction represented by force field parametrized upon ab initio calculations, (4)He/(3)He selectivity analyzed tunneling-corrected transition state...

A new spin-averaged potential energy surface (PES) for non-reactive O2(Σg−3) + collisions is presented. The formulated analytically according to the nature of principal interaction components, with main van der Waals contribution described through improved Lennard-Jones model. All parameters involved in formulation, having a physical meaning, have been modulated restricted variation ranges, exploiting combined analysis experimental and ab initio reference data. PES shown be able reproduce...

Intermolecular potentials for the three lowest multiplet states (singlet, triplet and quintet) of O2(3Σ−g)–O2(3Σ−g) dimer have been investigated in detail by means high level ab initio calculations. The methods used include MRCI, ACPF, CASPT2, using different active spaces basis sets. results quintet state are compared with benchmark CCSD(T) As expected, former do not account accurately dispersion interactions, although CASPT2 method performs better than CI based ones. On other hand, it is...

Completely ab initio global potential energy surfaces (PESs) for the singlet and triplet spin multiplicities of rigid O(2)((3)Σ(g)(-))+O(2)((3)Σ(g)(-)) are reported first time. They have been obtained by combining an accurate restricted coupled cluster theory with singles, doubles, perturbative triple excitations [RCCSD(T)] quintet [Bartolomei et al., J. Chem. Phys. 128, 214304 (2008)] complete active space second order perturbation (CASPT2) or, alternatively, multireference configuration...

Concentration photovoltaic (CPV) systems might produce quite uneven irradiance distributions (both on their level and spectral distribution) the solar cell. This effect can be even more evident when CPV system is slightly off-axis, since they are often designed to assure good uniformity only at normal incidence. The non-uniformities both in absolute content produced by systems, originate electrical losses multi-junction cells (MJSC). works focused integration of ray-tracing methods for...

Coronene-doped helium clusters have been studied by means of classical and quantum mechanical (QM) methods using a recently developed He–C24H12 global potential based on the use optimized atom-bond improved Lennard-Jones functions. Equilibrium energies geometries at local minima for systems with up to 69 He atoms were calculated an evolutive algorithm basin-hopping approach compared results from path integral Monte Carlo (PIMC) calculations 2 K. A detailed analysis performed smallest sizes...

The vibrational predissociation of the HeBr2 van der Waals complex is studied by means both accurate and approximate three dimensional quantum mechanical calculations. Simple atom–atom potentials have been tested for matching experimental measurements at low Br2 excitations. fragmentation dynamics when bromine subunit close to its B state dissociation limit then explored compared with experiments. For intermediate states v, good agreement most data (spectral shifts, lifetimes, average...

The rovibrational structure of the He2Cl2 van der Waals cluster in X and B electronic states is studied by means full dimensional quantum-mechanical calculations. smallest containing helium for which rotationally state-resolved data are available effects Bose statistics important. wave functions exhibit quite large amplitude motions, particularly He–He bending mode [associated with angle formed between two He–(center mass Cl2) bonds]. preferred geometry ground state planar, axis...

Adsorption of molecular hydrogen on coronene studied with a new potential energy surface. Path integral Monte Carlo and basin-hopping calculations have been performed to investigate energies structures the corresponding (H₂)_N-coronene clusters.

Accurate intermolecular potentials for the lowest three multiplet states of O2−O2 dimer have been produced on basis ab initio calculations. The quintet potential was taken from previous highly correlated CCSD(T) In this work, we perform MRCI calculations, with large sets including bond functions, singlet and triplet states, which are multireference character. As expected size inconsistency lack higher order excitations limit accuracy specifically in describing long range interactions. We...

A new potential energy surface (PES) for the quintet state of rigid O2(Σg−3)+O2(Σg−3) has been obtained using restricted coupled-cluster theory with singles, doubles, and perturbative triple excitations [RCCSD(T)]. large number relative orientations monomers (65) intermolecular distances (17) have considered. spherical harmonic expansion interaction built from ab initio data. It involves 29 terms, as a consequence anisotropy interaction. The spherically averaged term agrees quite well one...

Solvation of Cs+ ions inside helium droplets has been investigated both experimentally and theoretically. On the one hand, mass spectra doped clusters ionized with a crossed electron beam, HeNCs+, have recorded for sizes up to N = 60. The analysis ratio between observed peaks each size reveals evidences closure first solvation shell when 17 He atoms surround alkali ion. other we obtained energies geometrical structures title by means basin-hopping, diffusion Monte Carlo (DMC), path integral...

Recent data have determined that the structure of high pressure $\epsilon$ phase solid oxygen consists clusters composed four O$_2$ molecules. This finding has opened question about nature intermolecular interactions within molecular tetramer. We use multiconfigurational ab initio calculations to obtain an adequate characterization ground singlet state (O$_2$)$_4$ which is compatible with non magnetic character phase. In contrast previous suggestions implying chemical bonding, we show a van...

The collision dynamics of 17\documentclass[12pt]{minimal}\begin{document}$\text{O}_2(^3\Sigma _g^-) + ^{17}\text{O}_2(^3\Sigma _g^-)$\end{document}O2(3Σg−)+17O2(3Σg−) in the presence a magnetic field is studied within close-coupling formalism range between 10 nK and 50 mK. A recent global ab initio potential energy surface (PES) employed its effect on analyzed compared with previous calculations where an experimentally derived PES was used [T. V. Tscherbul et al., New J. Phys 134, 055021...

Clusters formed by the combination of rare gas (RG) atoms He, Ne, Ar, and Kr on coronene have been investigated means a basin-hopping algorithm path integral Monte Carlo calculations at T = 2 K. Energies geometries obtained role played specific RG-RG RG-coronene interactions final results is analysed in detail. Signatures diffuse behavior He surface are contrast with localization heavier species, Ar Kr. The observed coexistence various for Ne suggests motion RG multi-well potential energy...

We report on a combined experimental and theoretical study of Li$^+$ ions solvated by up to 50 He atoms. The experiments show clear enhanced abundances associated with He$_n$Li$^+$ clusters where $n=2$, 6, 8, 14. find that classical methods, e.g.\ Basin-Hopping (BH), give results qualitatively agree quantum mechanical methods such as path integral Monte Carlo, diffusion Carlo free energy, regarding both energies the solvation structures are formed. theory identifies particularly stable for...

Pump-probe spectra of HeBr2 in vibrational states v′=10 and 39 through 48 the B electronic state are reported fragment rotational distributions from predissociation cluster extracted measured E(0g+)←B(3Π0u+) Br2. The experimental results compared to theoretical calculations on B←X using atom-atom model potentials performing a thermal average over transitions that contribute net excitation. Very good agreement between experiment theory is obtained, except region v′=44, where Δv=−1 channel...