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Symmetry
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Quantum Chemistry
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Quantum Chemistry

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Chemistry: Symmetry/Asymmetry".

Deadline for manuscript submissions: closed (15 February 2021) | Viewed by 15315

Special Issue Editor

Dr. Pedro E.M. Lopes

E-Mail Website
Guest Editor
Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
Interests: computational chemistry; biophysics; drug-design; quantum mehanics

Special Issue Information

Dear Colleagues,

Quantum Chemistry has become an important tool in multiple scientific areas such as chemistry, biochemistry, and materials. In a time when computational power is reaching the exascale, quantum chemistry faces new challenges and opportunities, in particular, the need for new algorithms which are suitable for highly parallel environments. This is an exciting time for quantum chemists since the combination of additional computer power and fast algorithms will allow new technological developments in areas that have been out of reach. We thus invite contributions detailing the latest progress in quantum chemistry including on algorithms, software, and applications. All methods from different backgrounds, such as semi-empirical, DFT or coupled-cluster, are welcome. Important are also contributions detailing the latest software implementations and capabilities. We seek contributions on the latest uses of quantum mechanical methods to study large and complex systems, including applications to chemistry, biochemistry, drug discovery, and materials modeling and design. Please note that all submitted papers must be within the general scope of the Symmetry journal.

Dr. Pedro E.M. Lopes
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Quantum chemistry
  • Ab initio
  • Density functional theory (DFT)
  • Basis set
  • Coupled cluster
  • Semi-empirical methods
  • Hartree–Fock
  • Electron repulsion integrals
  • Ab initio molecular dynamics

Published Papers (6 papers)

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Research

13 pages, 1955 KiB  
Article
Covalently Bonded Fullerene Nano-Aggregates (C60)n: Digitalizing Their Energy–Topology–Symmetry
by Denis Sh. Sabirov, Ottorino Ori, Alina A. Tukhbatullina and Igor S. Shepelevich
Symmetry 2021, 13(10), 1899; https://doi.org/10.3390/sym13101899 - 09 Oct 2021
Cited by 14 | Viewed by 2405
Abstract
Fullerene dimers and oligomers are attractive molecular objects with an intermediate position between the molecules and nanostructures. Due to the size, computationally assessing their structures and molecular properties is challenging, as it currently requires high-cost quantum chemical techniques. In this work, we have [...] Read more.
Fullerene dimers and oligomers are attractive molecular objects with an intermediate position between the molecules and nanostructures. Due to the size, computationally assessing their structures and molecular properties is challenging, as it currently requires high-cost quantum chemical techniques. In this work, we have jointly studied energies, topological (Wiener indices and roundness), and information theoretic (information entropy) descriptors, and have obtained regularities in triad ‘energy–topology–symmetry’. We have found that the topological indices are convenient to indicating the most and least reactive atoms of the fullerene dimer structures, whereas information entropy is more suitable to evaluate odd–even effects on the symmetry of (C60)n. Quantum chemically assessed stabilities of selected C120 structures, as well as linear and zigzag (C60)n, are discussed. Full article
(This article belongs to the Special Issue Quantum Chemistry)
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22 pages, 4107 KiB  
Article
Some Aryl-1,2,4-triazol-1-ium Phenacylids in Binary Hydroxyl Solvent Mixtures. Computational and Spectral Study
by Dana Ortansa Dorohoi, Dan Gheorghe Dimitriu, Ana Cezarina Morosanu, Nicoleta Puica Melniciuc, Ion Hurjui, Mihaela Miron, Gabriel Grigore Mariciuc, Valentina Closca and Corina Cheptea
Symmetry 2021, 13(9), 1656; https://doi.org/10.3390/sym13091656 - 08 Sep 2021
Cited by 4 | Viewed by 1370
Abstract
Four carbanion monosubstituted p-aryl-1,2,4-triazol-1-ium methylids are subjected to a comparative study between their spectral and quantum-mechanical parameters in order to obtain more information about their structural features in hydroxyl solvents as water and ethanol and also on the nature of electronic absorption transitions [...] Read more.
Four carbanion monosubstituted p-aryl-1,2,4-triazol-1-ium methylids are subjected to a comparative study between their spectral and quantum-mechanical parameters in order to obtain more information about their structural features in hydroxyl solvents as water and ethanol and also on the nature of electronic absorption transitions from the visible range. The quantum mechanical analysis, made by the Spartan’14 program, established a series of molecular parameters of the studied ylids important for their reactivity and for intermolecular interactions with hydroxyl liquids. An extensive solvatochromic study of 1,2,4-triazol-1-ium ylids is impossible due to their limited solubility in liquids. Binary solvent mixtures of water and ethanol with known solvent parameters from the literature were used for this study. The electronic absorption spectra in binary solvents water and ethanol were used to establish the influence of intermolecular interactions on the spectral characteristics of the studied methylids and also on the composition of their first solvation shell in ternary solutions. The difference between the interaction energies in molecular pairs ylid–water and ylid–ethanol was determined based on the statistical cell model applied to the ternary solutions of the type of ylid + water + ethanol. The obtained values are very small due to the hydroxylic nature of the two solvents. Full article
(This article belongs to the Special Issue Quantum Chemistry)
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14 pages, 1749 KiB  
Article
Two Faces of Water in the Formation and Stabilization of Multicomponent Crystals of Zwitterionic Drug-Like Compounds
by Artem O. Surov, Nikita A. Vasilev, Andrei V. Churakov, Olga D. Parashchuk, Sergei V. Artobolevskii, Oleg A. Alatortsev, Denis E. Makhrov and Mikhail V. Vener
Symmetry 2021, 13(3), 425; https://doi.org/10.3390/sym13030425 - 06 Mar 2021
Cited by 14 | Viewed by 3433
Abstract
Two new hydrated multicomponent crystals of zwitterionic 2-aminonicotinic acid with maleic and fumaric acids have been obtained and thoroughly characterized by a variety of experimental (X-ray analysis and terahertz Raman spectroscopy) and theoretical periodic density functional theory calculations, followed by Bader analysis of [...] Read more.
Two new hydrated multicomponent crystals of zwitterionic 2-aminonicotinic acid with maleic and fumaric acids have been obtained and thoroughly characterized by a variety of experimental (X-ray analysis and terahertz Raman spectroscopy) and theoretical periodic density functional theory calculations, followed by Bader analysis of the crystalline electron density) techniques. It has been found that the Raman-active band in the region of 300 cm−1 is due to the vibrations of the intramolecular O-H...O bond in the maleate anion. The energy/enthalpy of the intermolecular hydrogen bonds was estimated by several empirical approaches. An analysis of the interaction networks reflects the structure-directing role of the water molecule in the examined multicomponent crystals. A general scheme has been proposed to explain the proton transfer between the components during the formation of multicomponent crystals in water. Water molecules were found to play the key role in this process, forming a “water wire” between the COOH group of the dicarboxylic acid and the COO– group of the zwitterion and the rendering crystal lattice of the considered multicomponent crystals. Full article
(This article belongs to the Special Issue Quantum Chemistry)
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26 pages, 5513 KiB  
Article
Symmetry/Asymmetry of the NHN Hydrogen Bond in Protonated 1,8-Bis(dimethylamino)naphthalene
by Patrycja Piękoś, Aneta Jezierska, Jarosław J. Panek, Eugene A. Goremychkin, Alexander F. Pozharskii, Alexander S. Antonov, Peter M. Tolstoy and Aleksander Filarowski
Symmetry 2020, 12(11), 1924; https://doi.org/10.3390/sym12111924 - 23 Nov 2020
Cited by 8 | Viewed by 2756
Abstract
Experimental and theoretical results are presented based on vibrational spectra and motional dynamics of 1,8-bis(dimethylamino)naphthalene (DMAN) and its protonated forms (DMANH+ and the DMANH+ HSO4− complex). The studies of these compounds have been performed in the gas phase and [...] Read more.
Experimental and theoretical results are presented based on vibrational spectra and motional dynamics of 1,8-bis(dimethylamino)naphthalene (DMAN) and its protonated forms (DMANH+ and the DMANH+ HSO4− complex). The studies of these compounds have been performed in the gas phase and solid-state. Spectroscopic investigations were carried out by infrared spectroscopy (IR), Raman, and incoherent inelastic neutron scattering (IINS) experimental methods. Density functional theory (DFT) and Car–Parrinello molecular dynamics (CPMD) methods were applied to support our experimental findings. The fundamental investigations of hydrogen bridge vibrations were accomplished on the basis of isotopic substitutions (NH → ND). Special attention was paid to the bridged proton dynamics in the DMANH+ complex, which was found to be affected by interactions with the HSO4− anion. Full article
(This article belongs to the Special Issue Quantum Chemistry)
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23 pages, 3501 KiB  
Article
Computational and Spectral Means for Characterizing the Intermolecular Interactions in Solutions and for Estimating Excited State Dipole Moment of Solute
by Dana Ortansa Dorohoi, Dorina Emilia Creanga, Dan Gheorghe Dimitriu, Ana Cezarina Morosanu, Antonina Gritco-Todirascu, Gabriel Grigore Mariciuc, Nicoleta Puica Melniciuc, Elena Ardelean and Corina Cheptea
Symmetry 2020, 12(8), 1299; https://doi.org/10.3390/sym12081299 - 04 Aug 2020
Cited by 12 | Viewed by 2360
Abstract
The results obtained both in quantum chemical computation and in solvatochromic study of pyridinium di-carbethoxy methylid (PCCM) are correlated in order to estimate the electric dipole moment in the excited state of this molecule. This estimation is made by a variational method in [...] Read more.
The results obtained both in quantum chemical computation and in solvatochromic study of pyridinium di-carbethoxy methylid (PCCM) are correlated in order to estimate the electric dipole moment in the excited state of this molecule. This estimation is made by a variational method in the hypothesis that the molecular polarizability does not change in time of the absorption process. Ternary solutions of PCCM in protic binary solvents are used here, both establishing the contribution of each type of interaction to the spectral shift and to characterize the composition of the first solvation shell of PCCM. Results are compared with those obtained before for other binary solvents. The difference between the interaction energies in molecular pairs of PCCM-active solvent and PCCM-less active solvent was also estimated based on the cell statistical model of the ternary solutions. Full article
(This article belongs to the Special Issue Quantum Chemistry)
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12 pages, 3376 KiB  
Article
First-Principles Calculations of High-Pressure Physical Properties of Ti0.5Ta0.5 Alloy
by Fang Yu and Yu Liu
Symmetry 2020, 12(5), 796; https://doi.org/10.3390/sym12050796 - 09 May 2020
Cited by 1 | Viewed by 1872
Abstract
In this paper, an in-depth theoretical study on some physical properties of Ti0.5Ta0.5 alloy with systematic symmetry under high pressure is conducted via first-principles calculations, and relevant physical parameters are calculated. The results demonstrate that the calculated parameters, including lattice [...] Read more.
In this paper, an in-depth theoretical study on some physical properties of Ti0.5Ta0.5 alloy with systematic symmetry under high pressure is conducted via first-principles calculations, and relevant physical parameters are calculated. The results demonstrate that the calculated parameters, including lattice parameter, elastic constants, and elastic moduli, fit well with available theoretical and experimental data when the Ti0.5Ta0.5 alloy is under T = 0 and P = 0 , indicating that the theoretical analysis method can effectively predict the physical properties of the Ti0.5Ta0.5 alloy. The microstructure and macroscopic physical properties of the alloy cannot be destroyed as the applied pressure ranges from 0 to 50GPa, but the phase transition of crystal structure may occur in the Ti0.5Ta0.5 alloy if the applied pressure continues to increase according to the TDOS curves and charge density diagram. The value of Young’s and shear modulus is maximized at P = 25   GPa . The anisotropy factors A ( 100 ) [ 001 ] and A ( 110 ) [ 001 ] are equal to 1, suggesting the Ti0.5Ta0.5 alloy is an isotropic material at 28 GPa, and the metallic bond is strengthened under high pressure. The present results provide helpful insights into the physical properties of Ti0.5Ta0.5 alloy. Full article
(This article belongs to the Special Issue Quantum Chemistry)
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