Papers by Patricio F Provasi
Modulation of the NLO properties of p-coumaric acid by the solvent effects and proton dissociation
Journal of Molecular Liquids
Extensionismo, Innovación y Transferencia Tecnológica
En este trabajo se propone el diseño de un dispositivo sencillo, factible de ser construido en el... more En este trabajo se propone el diseño de un dispositivo sencillo, factible de ser construido en el hogar y que sirve para medir el coeficiente de tensión superficial. Este dispositivo se basa en el método de Du Noüy-Padday, con una varilla en lugar de una argolla. Se realizó el experimento con el dispositivo construido y se introdujeron algunas correcciones, las que deben medirse previamente. El resultado que se obtuvo para la tensión superficial del agua dista aproximadamente 14% del valor experimental conocido, pero la sencillez del equipo y la realización del experimento en sí resultan un buen incentivo para una clase sobre el tema en los últimos años del nivel medio o los primeros del nivel universitario, en particular, al cuestionar al estudiante sobre el resultado obtenido y cómo mejorar la aproximación al valor conocido.
Molecular Physics, Jun 22, 2018
A theoretical study of FCCF:(H 2 O) n complexes, with n = 1 and 2, has been carried out by means ... more A theoretical study of FCCF:(H 2 O) n complexes, with n = 1 and 2, has been carried out by means of ab initio computational methods. Three kinds of interactions are observed in the complexes: H•••π and H•••F hydrogen bonds and O•••FC tetrel bonds. The indirect spin-spin coupling constants have been calculated at the CCSD/aug-cc-pVTZ-J computational level. Special attention has been paid to the dependence of the different intramolecular coupling constants in FCCF on the distance between the coupled nuclei and the presence or absence of water molecules. The exceptional sensitivity shown by these coupling constants to the presence of water molecules is quite notorious and can provide information on the bonding structure of the molecule.
Nonlinear optical response of α-terpinolene and β-phellandrene chromophores: An octupolar gas-to-solvent enhancement able to retain light conduction
Optik
On the axial chirality of leucoindigo
Journal of Computational Chemistry
The diagonal components and the trace of two tensors which account for chiroptical response of th... more The diagonal components and the trace of two tensors which account for chiroptical response of the leucoindigo molecule that is, static anapole magnetizability, and dynamic electric dipole‐magnetic dipole polarisability depending on the frequency of impinging light, are a function of the dihedral angle of torsion about the central CC bond, assumed to lie in the direction of the coordinate system. They vanish for symmetry reasons at and , corresponding respectively to and point group symmetries, that is, cis and trans conformers characterized by the presence of molecular symmetry planes. Nonetheless, diagonal components and average value of static anapole polarizability and optical rotation tensors vanish at , where leucondigo is unquestionably chiral from the geometrical viewpoint. Vanishing values of the average chiroptical properties have been observed also in the proximity of other angles. Attempts have been made to explain the occurrence of accidental zeros of chiroptical prope...
A NMR hybrid J-coupling alternation (hJCA) parameter linearly correlated to properties of intermolecular H-bonded chains
Computational and Theoretical Chemistry
Libro de resúmenes de la 104ª Reunión de la Asociación Física Argentina, 2019
Libro de resúmenes de la 104ª Reunión de la Asociación Física Argentina, 2019
Sci, 2021
Glycine in its neutral form can exist in the gas phase while its zwitterion form is more stable i... more Glycine in its neutral form can exist in the gas phase while its zwitterion form is more stable in water solution, but how many waters are actually necessary to stabilize the zwitterionic structure in the gas phase? Are the intramolecular isotropic spin spin coupling constants sensitive enough to accuse the change in the environment? or the conformer observed? These and related questions have been investigated by a computational study at the level of density functional theory employing the B3LYP functional and the 6-31++G**-J basis set. We found that at least two water molecules explicitly accounted for in the super-molecule structure are necessary to stabilize both conformers of glycine within a water polarizable continuum model. At least half of the SSCCs of both conformers are very stable to changes in the environment and at least four of them differ significantly between Neutral and Zwitterion conformation.
Journal of Chemical Theory and Computation, 2019
It is shown that the anapolar interaction of the electrons of a molecule with an external uniform... more It is shown that the anapolar interaction of the electrons of a molecule with an external uniform magnetic field B and a uniform curl C = ∇ × B ′ determines different thermodynamical stabilization of the ground state for the enantiomers and diastereoisomers of a chiral molecule. A series of potential candidates for enantioselective syntheses has been investigated in a computational study at SCF-HF, B3LYP and various coupled cluster approaches to determine the energy difference between different enantiomers and diastereoisomers. The calculations show that these differences are very small for B and C presently available, but approximately 3 orders of magnitude bigger than those determined by parity violation effects. The chances that enantioselective synthesis may be attempted in the future are discussed. Recognition of anapolar interaction in chiral molecules via measurements of induced magnetic dipole moment in ordered phase may become possible in the presence of nonuniform magnetic field with strong gradient.
The Journal of Physical Chemistry A, 2017
The trace of tensors which account for chiroptical response of the H 2 O 2 molecule is a function... more The trace of tensors which account for chiroptical response of the H 2 O 2 molecule is a function of the HO-OH dihedral angle. It vanishes at • and • , due to the presence of molecular symmetry planes, but also for values in the range 90 • − 100 • of this angle, in which the molecule is unquestionably chiral. Such an atypical effect is caused by counterbalancing contributions of diagonal tensor components with nearly maximal magnitude but opposite sign, determined by electron flow in open or closed helical paths, and associated with induced electric and magnetic dipole moments and anapole moments. For values of dihedral angle external to the 90 • − 100 • interval, the helical paths become smaller in size, thus reducing the amount of cancellation among diagonal components. Shrinking of helical paths determines the appearence of extremum values of tensor traces approximately at 50 • and 140 • dihedral angles.
The Journal of chemical physics, Jan 7, 2014
Calculations have been carried out for C4H4X2 cyclic molecules, with X=O, S, Se, and Te, characte... more Calculations have been carried out for C4H4X2 cyclic molecules, with X=O, S, Se, and Te, characterized by the presence of magnetic-field induced toroidal electron currents and associated orbital anapole moments. The orbital anapole induced by a static nonuniform magnetic field B, with uniform curl C=∇×B, is rationalized via a second-rank anapole magnetizability tensor a(αβ), defined as minus the second derivative of the second-order interaction energy with respect to the components C(α) and B(β). The average anapole magnetizability a̅ equals -χ̅, the pseudoscalar obtained by spatial averaging of the dipole-quadrupole magnetizability χ(α,βγ). It has different sign for D and L enantiomeric systems and can therefore be used for chiral discrimination. Therefore, in an isotropic chiral medium, a homogeneous magnetic field induces an electronic anapole A(α), having the same magnitude, but opposite sign, for two enantiomorphs.
Study of geometries and electronic properties of AgSin clusters using DFT/TB
International Journal of Quantum Chemistry, 2010
We present a theoretical study of the structures of silver silicon clusters, AgSin, n = 1–15, usi... more We present a theoretical study of the structures of silver silicon clusters, AgSin, n = 1–15, using density functional tight binding methods. We discuss in detail the search for silicon clusters stabilized by silver dopage, their dissociation paths, and electronic properties. We also investigate the properties of silver encapsulated structures and compare them with those obtained when replacing the silver atom by different metals. Our results are checked against experimental measurements when available. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical Chemistry Accounts, 2018
We present the results of a computational study of the NMR properties of glycine in water solutio... more We present the results of a computational study of the NMR properties of glycine in water solution at the level of density functional theory employing the B3LYP functional and the 6-31G(d,p) and pcSseg-2 basis sets, describing the solvent either via the PCM continuous solvation model or PCM with additional explicit water molecules hydrogen bonded to the solute. We observe that the solvent causes considerable changes in the predicted magnetic shieldings and that the results depend significantly on the number of solvent molecules included in the quantum mechanical treatment. Keywords Chemical shift • PCM • pcSseg-2 basis sets 1 Introduction Amino acids are some of the fundamental bricks of life carrying out much of the functions in cells and therefore in living organisms. Glycine, in particular,
Journal of Computational Chemistry, 2018
In this article, the RPA(D) and HRPA(D) models for the calculation of linear response functions a... more In this article, the RPA(D) and HRPA(D) models for the calculation of linear response functions are presented. The performance of the new RPA(D) and HRPA(D) models is compared to the performance of the established RPA, HRPA, and SOPPA models in calculations of indirect nuclear spin-spin coupling constants using the CCSD model as a reference. The doubles correction offers a significant improvement on both the RPA and HRPA models; however, the improvement is more dramatic in the case of the RPA model. For all coupling types investigated in this study, the results obtained using the HRPA(D) model are comparable in accuracy to those given by the SOPPA model, while requiring between 30% and 90% of the calculation time needed for SOPPA. The RPA(D) model, while of slightly lower accuracy compared to the CCSD model than HRPA(D), offered calculation times of only approximately 25% of those required for SOPPA for all the investigated molecules.
Extensionismo, Innovación y Transferencia Tecnológica, 2021
En prácticamente cualquier curso de termodinámica aparece el tema de dilatación, en particular la... more En prácticamente cualquier curso de termodinámica aparece el tema de dilatación, en particular la dilatación lineal. Pero también resulta de mucha importancia en la naturaleza ya que ésta se toma muy seriamente el tema al crear seres capaces de mantener constante su temperatura. Con la ayuda de materiales de descarte logramos realizar un dilatómetro que presenta una precisión muy alta y nos permite estimar el coeficiente de dilatación de, por ejemplo, el acero con una precisión inferior al 6%.
Análisis empírico de algoritmos de inversión de matrices, aplicados al cálculo de propiedades moleculares
Fil: Godoy, Maria Viviana. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Natura... more Fil: Godoy, Maria Viviana. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina
High‐Level Electron Correlation of the Indirect Nuclear Spin‐Spin Coupling Constants in Some Small Diboranes and Lithium‐Doped Diboranes
We have investigated the spin-spin coupling constants (SSCC's) of diborane(4) and diborane(6)... more We have investigated the spin-spin coupling constants (SSCC's) of diborane(4) and diborane(6), their Li-doped counterparts, and the dimerization of diborane(6), using the second order polarization propagator approximation with coupled cluster singled and double [SOPPA(CCSD)] substitutions. We employed an adapted basis set to perform the calculations of their SSCC's. Energetically, from optimized structures at second-order Møller-Plesset perturbation theory, our results indicate that the stable isomers of diborane(4) may exist as independent molecular entities, separate by ~20 kJ/mol, obtained in our best level of calculation. Distinct geometric configurations and energetic stability are well related to the nuclear coupling mechanism in these diborane compounds. We found that dimerization of diborane(6) is possible with different symmetries, although it does not significantly change the geometric parameters of the monomers. This is also confirmed by the SSCC's calculations with SOPPA(CCSD).Fil: Santos Neto, Antonio P.. Universidade Federal da Bahia; BrasilFil: Rivelino, Roberto. Universidade Federal da Bahia; BrasilFil: Pagola, Gabriel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Provasi, Patricio Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura. Departamento de Física; Argentin
This is the documentation for the Dalton quantum chemistry program-part of the DAL-TON2013 progra... more This is the documentation for the Dalton quantum chemistry program-part of the DAL-TON2013 program suite-for computing many types of Hartree-Fock, Kohn-Sham DFT, MCSCF, NEVPT2, MP2, MP2-R12, CI, CC, CC-R12 wave functions. and for calculating molecular properties and potential energy surfaces. We emphasize here the conditions under which the program is distributed. It is furnished for your own use, and you may not redistribute it further, either in whole or in part. Any one interested in obtaining the DALTON2013 program suite should check out the Dalton homepage at http://www.daltonprogram.org. Any use of the program that results in published material should cite the following:
Wiley interdisciplinary reviews. Computational molecular science, 2014
Dalton is a powerful general-purpose program system for the study of molecular electronic structu... more Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, Møller-Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied ...
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Papers by Patricio F Provasi