A5017840103- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Synthesis and Properties of Aromatic Compounds
- Advanced NMR Techniques and Applications
- Atmospheric Ozone and Climate
- Graphene research and applications
- Inorganic Fluorides and Related Compounds
- Quantum, superfluid, helium dynamics
- Fullerene Chemistry and Applications
- Molecular Junctions and Nanostructures
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Laser Applications
- Molecular spectroscopy and chirality
- Atomic and Molecular Physics
- Magnetism in coordination complexes
- Boron and Carbon Nanomaterials Research
- Solid-state spectroscopy and crystallography
- Atmospheric chemistry and aerosols
- Machine Learning in Materials Science
- Astrophysics and Star Formation Studies
- Catalytic Processes in Materials Science
- Quantum and electron transport phenomena
- Various Chemistry Research Topics
- Crystallography and molecular interactions
- Carbon Nanotubes in Composites
Universitat de València
2011-2024
Parc Científic de la Universitat de València
2010-2018
Pulse Biosciences (United States)
2014
Stanford University
2014
Norwegian University of Science and Technology
2014
Hospital Universitario Doctor Peset
2012
Aarhus University
1994
Université Toulouse III - Paul Sabatier
1990
Centre National de la Recherche Scientifique
1990
Dalton is a powerful general-purpose program system for the study of molecular electronic structure at Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, Møller-Plesset, configuration-interaction, and coupled-cluster levels theory. Apart from total energy, wide variety properties may be calculated using these electronic-structure models. Molecular gradients Hessians are available geometry optimizations, dynamics, vibrational studies, whereas magnetic resonance optical...
We demonstrate that substantial computational savings are attainable in electronic structure calculations using a Cholesky decomposition of the two-electron integral matrix. In most cases, effort involved calculating is less than construction one Fock matrix direct O(N2) procedure.
Coupled cluster singles and doubles linear response (CCLR) calculations have been carried out for excitation energies dipole transition strengths the lowest excitations in LiH, CH+, C4 results compared with from a CI-like approach to equation of motion coupled (EOMCC). The are similar two approaches single molecule on small systems. However, CCLR gives size-intensive strengths, while EOMCC formalism does not. Thus, can give unphysically e.g., sequence noninteracting LiH systems we obtained...
Algorithms for calculating singlet excitation energies in the coupled cluster singles and doubles (CCSD) model are discussed an implementation of atomic-integral direct algorithm is presented. Each energy calculated at a cost comparable to that CCSD ground-state energy. Singlet benzene using up 432 basis functions. Basis-set effects order 0.2 eV observed when increased from augmented polarized valence double-zeta (aug-cc-pVDZ) triple-zeta (aug-cc-pVTZ) quality. The correlation problem...
Using Cholesky decomposition and density fitting to approximate the electron repulsion integrals, an implementation of complete active space self-consistent field (CASSCF) method suitable for large-scale applications is presented. Sample calculations on benzene, diaquo-tetra-mu-acetato-dicopper(II), diuraniumendofullerene demonstrate that approximations allow larger basis sets systems be treated at CASSCF level theory with controllable accuracy. While strict error control inherent property...
We use Cholesky decomposition of the density matrix in atomic orbital basis to define a new set occupied molecular coefficients. Analysis resulting orbitals ("Cholesky orbitals") demonstrates their localized character inherited from sparsity matrix. Comparison with results traditional iterative localization schemes shows minor differences respect number suitable measures locality, particularly scaling system size pair domains used local correlation methods. The procedure for generating...
An efficient and highly vectorized implementation of the coupled cluster singles doubles (CCSD) model using a direct atomic integral technique is presented. The minimal number n6 processes has been implemented for most time consuming terms point group symmetry used to further reduce operation counts memory requirements. significantly increased application range CCSD method illustrated with sample calculations on several systems more than 500 basis functions. Furthermore, we present basic...
A new implementation of the approximate coupled cluster singles and doubles CC2 linear response model using Cholesky decomposition two-electron integrals is presented. Significantly reducing storage demands computational effort without sacrificing accuracy compared to conventional model, algorithm well suited for large-scale applications. Extensive basis set convergence studies are presented static frequency-dependent electric dipole polarizability benzene C60, optical rotation CNOFH2...
We present a general formalism where different levels of coupled cluster theory can be applied to parts the molecular system. The system is partitioned into subsystems by Cholesky decomposition one-electron Hartree-Fock density matrix. In this way divided across chemical bonds without discontinuities arising. wave function defined in terms operators for each part and these are determined from set equations. total fulfills Pauli-principle all borders electron correlation. develop associated...
We present a novel approach to the calculation of Coulomb and exchange contributions total electronic energy in self consistent field density functional theory. The numerical procedure is based on Cholesky decomposition involves specific Hadamard product matrices that enter expression. In this way, we determine an auxiliary basis obtain dramatic reduction size as compared resolution identity (RI) method. Although determined from expression, have complete control errors gradient or Fock...
Multiscale modeling and simulation (MMS) combining B97-D/TZV2P DFT calculations molecular dynamics simulations are performed to investigate the adsorption of hydrogen over coronene as a model graphene.
High-level quantum-chemical methods show that the binding in inclusion complex of hexamethylbenzene (HMB) 6-cycloparaphenilacetylene (6-CPPA) cannot be explained only terms electrostatic interactions-caused by polarization associated to curved pi-conjugated systems-and dispersion forces is definitely needed. The theoretical description van der Waals interactions notoriously complicated and fact some DFT even predict existence relatively small supramolecular nanoring studied here. However, ab...
Decomposing the Hartree-Fock one-electron density matrix and a virtual pseudodensity matrix, we obtain an orthogonal set of normalized molecular orbitals with local character to be used in post-Hartree-Fock calculations. The applicability procedure is illustrated by calculating CCSD(T) energies CCSD properties reduced active spaces.
Different force fields for the graphene–CH<sub>4</sub> system are proposed including pseudo-atom and full atomistic models.
The interaction of CO with graphene was studied at different theoretical levels. Quantum-mechanical calculations on finite models the use coronene for coupled cluster and circumcoronene B97D showed that there no preferential site adsorption most important factor orientation relative to graphene. parallel preferred, binding energies around 9 kJ mol-1 CCSD(T) levels, which in good agreement experimental findings. From a large number CO-circumcoronene CO-CO interactions, computed distances...
We introduce an alternative to Almlöf and Häser’s Laplace transform decomposition of orbital energy denominators used in obtaining reduced scaling algorithms perturbation theory based methods. The new is on the Cholesky positive semidefinite matrices. show that have a particular short size-intensive decomposition. main advantage using decomposition, besides shorter expansion, systematic improvement results without penalties encountered when changing number integration points order control...
Abstract The local response to an external magnetic field normal the molecular plane of naphthalene and anthracene was investigated via current density shielding maps. Biot‐Savart law shows that deshielding caused by π‐ring currents in is stronger for α‐ than β‐protons due geometrical factors. tensor carbon nuclei both molecules strongly anisotropic its out‐of‐plane component determines up‐field chemical shift 13 C nuclear resonance spectra. flowing beyond C‐skeleton front a probe nucleus,...
We theoretically investigate graphene layers, proposing them as membranes of subnanometer size suitable for CH4/N2 separation and gas uptake. The observed potential energy surfaces, representing the intermolecular interactions within gaseous mixtures between these have been formulated by adopting so-called Improved Lennard-Jones (ILJ) potential, which is far more accurate than traditional potential. Previously derived ILJ force fields are used to perform extensive molecular dynamics...
Despite being considered completely rigid in most studies, graphene is really flexible leading to out-of-plane movements. In this work, the influence of such flexibility on adsorption methane and nitrogen studied using molecular dynamics. Indeed, we have used intramolecular force fields for with in-plane components that allow describing movements deformations sheets providing a more realistic description adsorbent. addition, intermolecular validated at CCSD(T) level are used. We show...
We use large-scale MP2 calculations to investigate the physisorption of molecular hydrogen on (9,0) defective carbon nanotubes (CNTs) C72H18. These large (supra)molecular systems are typically studied using conventional DFT methods, which do not describe well van der Waals interactions responsible for this process. Here we CCSD(T)-calibrated estimate binding energies by considering four structures (hydrogenated divacancy, octagon-pentagon, and two Stone-Wales defects). The largest...