A new embedding method to include local correlation in large systems is proposed. In this the density of whole system, calculated via functional theory approaches, partitioned two pieces, one corresponding subsystem interest and rest environment. second step, an potential obtained iteratively using as a driving force self-repulsion due difference, similar form proposed by Zhao et al. [Phys. Rev. 50, 2138 (1994)], obtain "exact" exchange-correlation functional. Such added Fock equation build...

Converged three-dimensional quantum mechanical calculations for photofragmentation of the Ne⋅⋅ICl van der Waals molecule in energy region electronically excited B(3∏0+) state ICl are presented and compared with experiments. Lifetimes final distributions fragments were determined vibrational predissociation from lowest level B(v′=2) channel. Good agreement between theory experiment was achieved using a sum atom–atom pairwise potentials. This potential surface predicts equilibrium geometry...

In this work a reliable full nine-dimensional potential energy surface for studying the dynamics of H(5)(+) is constructed, which completely symmetric under any permutation nuclei. For purpose, we develop triatoms-in-molecules method as an extension more common diatoms-in-molecules one, allows very accurate description asymptotic regions by including correctly charge-induced dipole and quadrupole interactions. Moreover, treatment provides semiquantitative all topological features global...

We performed path-integral molecular dynamics (PIMD) simulations in the NVT ensemble to investigate quantum solvation of Li2+ He nanoclusters at a low temperature 2 K. The interaction potentials were modeled using sum-of-potentials approach, incorporating automated learning ab initio-based models up three-body terms. Additionally, semiclassical quadratic Feynman-Hibbs approach was applied incorporate effects into classical computations effectively, enabling study HeNLi2+ complexes with 50...

Helium trimer bound states are calculated by means of a variational method described in terms atom pair coordinates and distributed Gaussian basis functions for zero total angular momentum. To show the feasibility this method, we also apply it to calculation first vibrational levels Ar3 Ne3 clusters. Special emphasis is made on study possible Efimov behavior excited state found He34 trimer. Geometrical configurations ground these rare gas trimers have been exhaustively studied owing proper...

Helium trimer bound states are calculated with a variational method described in terms of pair atom coordinates and distributed Gaussian functions by assuming zero total angular momentum. With the two-body interaction potential used, weakly state for dimer only two found. Although strictly speaking first excited is not an Efimov state, we show that this presents several characteristics behavior which extensively discussed present work. Special emphasis placed on main geometrical...

A variational treatment is presented to study bound and quasibound states of X1...BC...X2 van der Waals clusters, where X1 X2 are rare gas atoms BC a conventional diatomic molecule. The Hamiltonian operator, including all the degrees freedom, expressed in terms B–C relative vector bond coordinates which describe position each atom with respect center mass. In body-fixed reference system, Z axis parallel axis, matrix elements evaluated basis set functions takes into account symmetries system....

We apply a quasiclassical trajectory method to treat vibrational predissociation of the van der Waals molecule He⋅⋅⋅I2(B 3Π). In order compare with quantum mechanical calculations and experimental data, we have introduced rotational degree freedom by using an approximate treatment. The potential energy surface used was sum pairwise atom–atom potentials. initial conditions were selected at random taking into account previous quantal results. final distribution for I2 fragment total rate...

The lowest Σ+2 and Π2 electronic states of the HeBr molecule have been calculated by ab initio coupled cluster approach in conjunction with a series increasing size augmented correlation-consistent basis sets double through quintuple zeta quality. Different extrapolation formulas to complete set limit tested comparing estimated actual quality counterpoise corrected interaction energies. Frozen-core is checked performing calculations which all electrons are correlated. potential energy...

The time-dependent wave packet technique is applied to the Golden Rule treatment of vibrational predissociation. at time zero taken as product quasibound function and coupling inducing rate for predissociation can then be obtained by Fourier transform into energy domain autocorrelation function. method has been a model triatomic van der Waals molecule. It shown that when bound-state components are projected out, version approximation provides an alternative efficient treat intramolecular decay.

The dynamics of vibrational predissociation (VP) van der Waals (vdW) I2⋅⋅⋅Nen clusters is studied by means a quasiclassical trajectory approach. We assume near-equilibrium geometry that accounts for the I2 stretch and stretching bending modes rare gas atoms restricted to move along plane perpendicular axis. A sharp increase halfwidth observed n=9 together with certain stability n=8 cluster size respect dissociation. It would indicate existence first coordination shell Ne around containing...

A new method is proposed to partition the density of a system in two portions. The on each subsystem solution Fock equation modified by addition an embedding potential. This potential obtained iteratively minimizing difference between electronic densities total and sum subsystems. Thus, are at same time within procedure, guarantying v-representability partitioned. fact considerable improvement recently inversion technique, [O. Roncero, M. P. de Lara-Castells, Villarreal, F. Flores, J....

The structure, energetics, and spectroscopy of ground-state HeI2 molecule are analyzed from first principles. Ab initio methodology at CCSD(T) level theory was employed, large basis sets were used to compute the interaction energies. Scalar relativistic effects accounted for by effective core potentials iodine atoms. Recent experimental investigations rovibronic spectra have estimated binding energies 16.6 ± 0.6 16.3 cm−1 T-shaped linear isomers, respectively. Given extremely small...

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...

High-level ab initio molecular electronic structure calculations are performed for Rg–Br2 (Rg=He, Ne, Ar) complexes at CCSD(T) (coupled cluster using single and double excitations with a noniterative perturbation treatment of triple excitations) level theory. Specific augmented correlation consistent basis sets used each noble atom (Rg), supplemented an additional set bond functions. Effective-core potentials (ECPs), diffusion (sp) polarization (3df ) functions, have been employed the...

Accurate positions and nonradiative lifetimes of states belonging to the adiabatic A state LiH are estimated. The results coming from a Golden Rule treatment in scheme present excellent agreement with those obtained through diabatic close coupling calculation. That confirms accuracy reached both approaches also diabatic–adiabatic transformation. It involves, particular, an effective phase control that is needed properly estimate nonadiabatic couplings. Also, powerful numerical procedure...

The potential energy surfaces of the ground electronic state rare gas interhalogen van der Waals molecules, Rg–ICl (Rg=He, Ne), are calculated at CCSD(T) (coupled cluster using single and double excitations with a noniterative perturbation treatment triple excitations) level theory. Calculations have been performed specific augmented correlation consistent basis sets for noble atom (Rg), supplemented an additional set bond functions. For iodine zeta valence in conjunction large-core...

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 vibrational predissociation dynamics of the I2(B,v)–Ne2 complex is investigated for several levels I2, using a quasiclassical trajectory approach. time evolution population nascent I2 fragments calculated. A model proposed which reproduces results classical trajectories, and allows to obtain lifetimes associated with dissociation two van der Waals (vdW) bonds. are higher in general than experimental ones Zewail co-workers [J. Chem. Phys. 97, 8048 (1992)]. method appears overestimate...

The role played by the bosonic or fermionic character of He atoms surrounding a Br2(X) molecule is analyzed through vibrotational Raman spectra simulations. Quantum chemistry-type calculations reveal spin multiplicity to be chiefly responsible for drastic difference observed Grebenev et al. [Science 279, 2083 (1998)]] in rotational structure molecules embedded helium droplets.

Energetics and dynamics of van der Waals (vdW) I2⋅⋅⋅Hen clusters are studied in an approximate way by using a model that considers 2n+1 degrees freedom, is, the I2 stretch 2n stretching bending modes He atoms restricted to move along plane perpendicular axis. For n=2,3 configuration-interaction treatment is carried out obtain energy levels. n=4–8, ground-level energies estimated from those corresponding geometric relationships among n vdW bonds. A quasiclassical trajectory approach used...

Classical and path integral Monte Carlo (CMC, PIMC) "on the fly" calculations are carried out to investigate anharmonic quantum effects on thermal equilibrium structure of H5(+) cluster. The idea follow in our computations is based using a combination above-mentioned nuclear classical statistical methods, first-principles density functional (DFT) electronic calculations. interaction energies computed within DFT framework B3(H) hybrid functional, specially designed for hydrogen-only systems....

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.