Anionic radical and protonated form of molecular ozone. A nonempirical calculation taking into account the electronic correlation

1993 ◽  
Vol 34 (2) ◽  
pp. 198-202
Author(s):  
I. I. Zakharov ◽  
O. I. Kolbacina ◽  
T. N. Semenyuk ◽  
N. F. Tyupalo ◽  
G. M. Zhidomirov
Keyword(s):  
Protonated Form ◽  
Nonempirical Calculation ◽  
Electronic Correlation ◽  
Anionic Radical

Electronic Structure Benchmark Calculations of Inorganic and Biochemical Carboxylation Reactions

2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
David A. Sáez ◽  
Stefan Vogt-Geisse ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Electronic Structure ◽  
Chemical Reactions ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Energy ◽  
Basis Sets ◽  
Electronic Correlation ◽  
Correct Description ◽  
Carbon Dioxide Co2 ◽  
High Level

<div><div><div><p>Carboxylation reactions represent a very special class of chemical reactions that is characterized by the presence of a carbon dioxide (CO2) molecule as reactive species within its global chemical equation. These reactions work as fundamental gear to accomplish the CO2 fixation and thus to build up more complex molecules through different technological and biochemical processes. In this context, a correct description of the CO2 electronic structure turns out to be crucial to study the chemical and electronic properties associated with this kind of reactions. Here, a sys- tematic study of CO2 electronic structure and its contribution to different carboxylation reaction electronic energies has been carried out by means of several high-level ab-initio post-Hartree Fock (post-HF) and Density Functional Theory (DFT) calculations for a set of biochemistry and inorganic systems. We have found that for a correct description of the CO2 electronic correlation energy it is necessary to include post-CCSD(T) contributions (beyond the gold standard). These high-order excitations are required to properly describe the interactions of the four π-electrons as- sociated with the two degenerated π-molecular orbitals of the CO2 molecule. Likewise, our results show that in some reactions it is possible to obtain accurate reaction electronic energy values with computationally less demanding methods when the error in the electronic correlation energy com- pensates between reactants and products. Furthermore, the provided post-HF reference values allowed to validate different DFT exchange-correlation functionals combined with different basis sets for chemical reactions that are relevant in biochemical CO2 fixing enzymes.</p></div></div></div>

Study of potential curves by UHF type methods. CH4 molecule and its dissociation products

1986 ◽  
Vol 51 (4) ◽  
pp. 731-737
Author(s):  
Viliam Klimo ◽  
Jozef Tiňo
Keyword(s):  
Experimental Data ◽  
Quantum Chemistry ◽  
High Energy ◽  
Basis Set ◽  
Electronic Correlation ◽  
Exact Methods ◽  
Energy Parameters ◽  
Bond Functions ◽  
The Individual ◽  
Potential Curves

Geometry and energy parameters of the individual dissociation intermediate steps of CH4 molecule, parameters of the barrier to linearity and singlet-triplet separation of the CH2 molecule have been calculated by means of the UMP method in the minimum basis set augmented with the bond functions. The results agree well with experimental data except for the geometry of CH2(1A1) and relatively high energy values of CH(2II) and CH2(1A1) where the existence of two UHF solutions indicates a necessity of description of the electronic correlation by more exact methods of quantum chemistry.

scholarly journals Interplay between multipolar spin interactions, Jahn-Teller effect, and electronic correlation in a Jeff=32 insulator

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Dario Fiore Mosca ◽  
Leonid V. Pourovskii ◽  
Beom Hyun Kim ◽  
Peitao Liu ◽  
Samuele Sanna ◽  
...  
Keyword(s):  
Teller Effect ◽  
Electronic Correlation ◽  
Spin Interactions ◽  
Jahn Teller ◽  
Jahn Teller Effect

Vectorial measurements of speckle displacement by the 2-D electronic correlation method

1985 ◽  
Vol 24 (5) ◽  
pp. 660 ◽  
Author(s):  
Nobukatsu Takai ◽  
Toshimitsu Asakura
Keyword(s):  
Correlation Method ◽  
Electronic Correlation

Internally 2,5-Thienylene-Bridged [46]Decaphyrin: (Annuleno)annulene Network Consisting of Möbius Aromatic Thia[28]hexaphyrins and Strong Hückel Aromaticity of its Protonated Form

2017 ◽  
Vol 56 (12) ◽  
pp. 3232-3236 ◽  
Author(s):  
Takanori Soya ◽  
Hirotaka Mori ◽  
Yongseok Hong ◽  
Yun Hee Koo ◽  
Dongho Kim ◽  
...  
Keyword(s):  
Protonated Form

scholarly journals Meteoritic amino acids as chemical tracers of parent-body chemistries

2021 ◽  
Vol 502 (3) ◽  
pp. 4064-4073
Author(s):  
Y Ellinger ◽  
M Lattelais ◽  
F Pauzat ◽  
J-C Guillemin ◽  
B Zanda
Keyword(s):  
Amino Acids ◽  
Relative Stability ◽  
Density Functional ◽  
Minimum Energy ◽  
Protonated Form ◽  
Parent Body ◽  
Chemical Formula ◽  
Energy Principle ◽  
Chemical Tracers ◽  
Minimum Energy Principle

ABSTRACT The analysis of the organic matter of meteorites made it possible to identify over 70 amino acids (AA), including 8 of those found in living organisms. However, their relative abundances vary drastically with the type of the carbonaceous chondrite, even for isomers of same chemical formula. In this report, we address the question whether this difference may have its origin in the relative stability of these isomers according to the conditions they experienced when they were formed and after. To this end, we rely on the fact that for most of the species observed so far in the interstellar medium (ISM), the most abundant isomer of a given generic chemical formula is the most stable one (minimum energy principle, MEP). Using quantum density functional theory (DFT) simulations, we investigate the relative stability of the lowest energy isomers of alanine (Ala) and amino butyric acid (ABA) in the neutral, protonated, and zwitterionic structures together with corresponding nitrile precursors. It is shown that β-alanine and γ-ABA are the most stable in a protonated form, whereas α-AA are the most stable in the zwitterionic and nitrile structures. The different composition of the carbonaceous chondrites CIs and CMs could be linked to the chemical context of the aqueous alterations of the parent bodies.

Nonempirical calculation of structural, electric and spectral characteristics of diprazine

2009 ◽  
Vol 79 (7) ◽  
pp. 1519-1524
Author(s):  
Yu. D. Merkulova ◽  
E. V. Butyrskaya ◽  
V. F. Selemenev
Keyword(s):  
Spectral Characteristics ◽  
Nonempirical Calculation
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