A theoretical study of semiclassic models: Toward a quantum mechanical representation of chemical processes

2010 ◽  
Vol 111 (2) ◽  
pp. 263-271 ◽  
Author(s):  
R. Crespo ◽  
M.-C. Piqueras ◽  
J. M. Aulló ◽  
O. Tapia
Keyword(s):  
Theoretical Study ◽  
Chemical Processes ◽  
Quantum Mechanical ◽  
Quantum Mechanical Representation

scholarly journals Theoretical study of the dark photochemistry of 1,3-butadiene via the chemiexcitation of Dewar dioxetane

2015 ◽  
Vol 17 (28) ◽  
pp. 18653-18664 ◽  
Author(s):  
Pooria Farahani ◽  
Marcus Lundberg ◽  
Roland Lindh ◽  
Daniel Roca-Sanjuán
Keyword(s):  
Excited State ◽  
Molecular Basis ◽  
Theoretical Study ◽  
Chemical Processes ◽  
State Chemical

We report on the molecular basis of excited-state chemical processes that are induced by intramolecular chemiexcitation rather than by irradiation.

scholarly journals Experimental and theoretical study of Aspartic acid

2019 ◽  
Keyword(s):  
Aspartic Acid ◽  
Single Molecule ◽  
Dft Calculation ◽  
Theoretical Study ◽  
Quantum Mechanical ◽  
Experimental Ir ◽  
Vibrational Bands ◽  
Computational Research ◽  
Ir And Raman ◽  
Dielectric Environment

The aim of this research is to detect zwittterionic structure of the aspartic acid and confirm the experimental spectra with quantum chemical calculations. The experimental IR and Raman spectra of aspartic acid powder show no vibrational bands of OH and NH stretching in expected spectral region. We assume that zwitterionic structure of aspartic acid is responsible for lowering the frequencies of these vibrations. An extensive experimental and computational research supports this assumption. Our DFT calculation strongly suggests the need for the dielectric environment in order to stabilize the zwitterionic structure of a single molecule. The network of intermolecular hydrogen bonding between aspartic acid molecules provides this dielectric environment. The DFT quantum mechanical calculations corroborate this assumption by optimizing a four-member group of molecules, which also gives an explanation of broad IR spectrum lines.

Theoretical study of NO3− interacting with carbon nanotube

Open Physics ◽  
2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Silvete Guerini ◽  
David Azevedo ◽  
Maria Lima ◽  
Ivana Zanella ◽  
Josué Filho
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Quantum Mechanical ◽  
Mechanical Interaction ◽  
Electronic Density ◽  
Functional Theory ◽  
Consistent Field ◽  
The Density Functional Theory ◽  
Self Consistent Field ◽  
Field Form

AbstractThis paper deals with quantum mechanical interaction of no 3− with (5,5) and (8,0) swcnts. To perform this we have made an ab initio calculation based on the density functional theory. In these framework the electronic density plays a central role and it was obtained of a self-consistent field form. It was observed through binding energy that NO3− molecule interacts with each nanotube in a physisorption regime. We propose these swcnts as a potential filter device due to reasonable interaction with NO3− molecule. Besides this type of filter could be reusable, therefore after the filtering, the swcnts could be separated from NO3− molecule.

Theoretical Study of Stereoselectivity for Syn-Selective Cross-Aldol Reactions of Aldehydes Catalyzed by Chiral Diamine Organocatalysts

2013 ◽  
Vol 798-799 ◽  
pp. 59-62
Author(s):  
Cheng Yan Zhao ◽  
Ai Ping Fu ◽  
Hong Liang Li ◽  
Ping Wang ◽  
Yong Xu ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Enantiomeric Excess ◽  
Aldol Reactions ◽  
Quantum Mechanical ◽  
Computational Studies ◽  
Poor Agreement ◽  
Chiral Diamine ◽  
Direct Cross ◽  
The Subject ◽  
Chiral Diamines

Quantum mechanical calculations have been performed to study the stereoselectivities in the direct cross-aldol reactions of aldehydes catalyzed by simple chiral diamines. The detailed computational studies on the stereochemistry-controlling step of the subject reactions have been presented by DFT calculations at the B3LYP/6-31G* level. The poor agreement between the calculated and the observed diastereomeric ratio and enantiomeric excess values is obtained for all diamines catalysts. Further M06-2X calculations can provide a reasonable explanation for the observed syn-selectivities of the asymmetric cross-aldol reaction between propionaldehyde and 4-nitrobenzaldehyde.

An ultrafast spectroscopic and quantum mechanical investigation of multiple emissions in push–pull pyridinium derivatives bearing different electron donors

2015 ◽  
Vol 17 (32) ◽  
pp. 20981-20989 ◽  
Author(s):  
B. Carlotti ◽  
E. Benassi ◽  
A. Cesaretti ◽  
C. G. Fortuna ◽  
A. Spalletti ◽  
...  
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Electron Donors ◽  
Quantum Mechanical ◽  
Mechanical Investigation

An interconversion between rotamers in S1 was evidenced for a cationic push–pull pyrenyl derivative through a joint femtosecond fluorescence up-conversion and density functional theoretical study.

scholarly journals Excitation Spectrum of the Néel Ensemble of Antiferromagnetic Nanoparticles as Revealed in Mössbauer Spectroscopy

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Mikhail A. Chuev
Keyword(s):  
Absorption Spectra ◽  
Excitation Spectrum ◽  
Magnetic Moment ◽  
Equations Of Motion ◽  
Normal Modes ◽  
Quantum Mechanical ◽  
Solution Of Equations ◽  
Regular Precession ◽  
Macroscopic Quantum Effects ◽  
Quantum Mechanical Representation

The excitation spectrum of the Néel ensemble of antiferromagnetic nanoparticles with uncompensated magnetic moment is deduced in the two-sublattice approximation following the exact solution of equations of motion for magnetizations of sublattices. This excitation spectrum represents four excitation branches corresponding to the normal modes of self-consistent regular precession of magnetizations of sublattices and the continuous spectrum of nutations of magnetizations accompanying these normal modes. Nontrivial shape of the excitation spectrum as a function of the value of uncompensated magnetic moment corresponds completely to the quantum-mechanical calculations earlier performed. This approach allows one to describe also Mössbauer absorption spectra of slowly relaxing antiferromagnetic and ferrimagnetic nanoparticles and, in particular, to give a phenomenological interpretation of macroscopic quantum effects observed earlier in experimental absorption spectra and described within the quantum-mechanical representation.

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