Semi-empirical and ab initio quantum chemical characterisation of pyridine derivatives as HCl inhibitors of aluminium surface

2008 ◽  
Vol 870 (1-3) ◽  
pp. 23-30 ◽  
Author(s):  
E. Jamalizadeh ◽  
A.H. Jafari ◽  
S.M.A. Hosseini
Keyword(s):  
Ab Initio ◽  
Quantum Chemical ◽  
Pyridine Derivatives ◽  
Semi Empirical

scholarly journals Theoretical Simulation of the Zeke Spectra of Naphthalene From Single Vibronic Levels of S1

1999 ◽  
Vol 19 (1-4) ◽  
pp. 105-108 ◽  
Author(s):  
Fabrizia Negri ◽  
Marek Z. Zgierski
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Ground State ◽  
Quantum Chemical ◽  
Electronic States ◽  
Perturbative Expansion ◽  
Molecular Structures ◽  
Theoretical Simulation ◽  
Vibronic States ◽  
Semi Empirical

We present the simulations and analysis of the two-color ZEKE spectra of naphthalene, performed with the help of quantum chemical calculations of molecular parameters followed by the modelling of vibronic intensities. Ab initio and semi-empirical calculations were carried out to obtain molecular structures of neutral and ionic naphthalene, and vibronic perturbations that couple the electronic states. It is shown that the intensities, simulated with a model based on the perturbative expansion of vibronic states, nicely reproduce the observed spectra and contribute to reassign some of the ground state frequencies of naphthalene cation.

scholarly journals Studies on Simulation of Spectra of Some Organic Compounds

2019 ◽  
Vol 35 (6) ◽  
pp. 1655-1668
Author(s):  
Pradeep Kumar Gupta ◽  
Kishor Arora
Keyword(s):  
Ab Initio ◽  
Organic Compounds ◽  
Quantum Chemical ◽  
Theoretical Chemistry ◽  
Simulation Studies ◽  
Empirical Methods ◽  
Present Communication ◽  
Semi Empirical ◽  
Simulation Of Spectra

Quantum chemical viz. ab initio or semi-empirical based simulation studies are now prevailing among workers / scientists pursuing their studies in theoretical chemistry. These studies provide better insight for the compounds so far as the studies of their structural orother parameters are concern. Studies involving the packages developed on the basis of ab-initio or semi-empirical methods are proven to be more effective and as a better tool because of number of their advantages. The present communication includes the studies on synthesis or procurement along with the simulation of spectra viz. I.R. of some heterocyclic organic compounds.

Evaluation of Chemotherapeutic Activity of the Selected Bases’ Analogues of Nucleic Acids Supported by ab initio Various Quantum Chemical Calculations

2020 ◽  
Vol 16 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek
Keyword(s):  
Biological Activity ◽  
Nucleic Acids ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Principal Component ◽  
Polarizable Continuum Model ◽  
Activity Data ◽  
Qsar Models

Background: Pharmacological and physicochemical classification of bases’ selected analogues of nucleic acids is proposed in the study. Objective: Structural parameters received by the PCM (Polarizable Continuum Model) with several types of calculation methods for the structures in vacuo and in the aquatic environment together with the huge set of extra molecular descriptors obtained by the professional software and literature values of biological activity were used to search the relationships. Methods: Principal Component Analysis (PCA) together with Factor Analysis (FA) and Multiple Linear Regressions (MLR) as the types of the chemometric approach based on semi-empirical ab initio molecular modeling studies were performed. Results: The equations with statistically significant descriptors were proposed to demonstrate both the common and differentiating characteristics of the bases' analogues of nucleic acids based on the quantum chemical calculations and biological activity data. Conclusion: The obtained QSAR models can be used for predicting and explaining the activity of studied molecules.

Quantum chemical prediction of 2H-pyran vibration spectrum

1990 ◽  
Vol 55 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Vibrational Spectrum ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Vibration Spectrum ◽  
Equilibrium Geometry ◽  
Heterocyclic Molecule ◽  
Vibrational Transitions ◽  
Correlation Corrections

Ab initio MO optimalization of the 2H-pyran molecule leads to a defined equilibrium geometry of this so far not identified heterocyclic molecule and to a physical justification of its existence. More advanced nonempirical wavefunctions and temperature corrections indicate that heterocyclic molecule I is energetically less stable than non-cyclic isomers II and III. Wavenumbers of fundamental vibrational transitions of heterocycle I and also known (2E)-2,4-pentadienal (IIIb were calculated using 3-21 G wavefunctions. The vibrational spectrum of compound I is predicted on the basis of correlation corrections.

Theoretical analysis of means of preventing Si–C bond cleavage during polycondensation of organosilanes to organosilicas

2021 ◽  
Author(s):  
Soichi Shirai ◽  
Shinji Inagaki
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Bond Cleavage ◽  
Model Compounds ◽  
Analysis Of Means

Practical strategies for suppressing Si–C cleavage during the polycondensation of organosilanes were presented based on ab initio quantum chemical calculations of model compounds.

Ab initio quantum-chemical calculations of the energies and structures of 1,2-acetylenedithiol isomers

2009 ◽  
Vol 50 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Yu. V. Frolov ◽  
A. V. Vashchenko ◽  
A. G. Mal’kina ◽  
B. A. Trofimov
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical
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