Ab initio quantum chemical computations of substituent effects on triaziridine strain energy and heat of formation

2009 ◽  
Vol 11 (14) ◽  
pp. 2387 ◽  
Author(s):  
Roberto Peverati ◽  
Jay S. Siegel ◽  
Kim K. Baldridge
Keyword(s):  
Ab Initio ◽  
Quantum Chemical ◽  
Strain Energy ◽  
Substituent Effects ◽  
Heat Of Formation ◽  
Quantum Chemical Computations

Excitons in poly(para phenylene vinylene): a quantum-chemical perspective based on high-level ab initio calculations

2016 ◽  
Vol 18 (4) ◽  
pp. 2548-2563 ◽  
Author(s):  
Stefanie A. Mewes ◽  
Jan-Michael Mewes ◽  
Andreas Dreuw ◽  
Felix Plasser
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Phenylene Vinylene ◽  
High Level ◽  
Quantum Chemical Computations

Exciton analyses of high-level quantum-chemical computations for poly(paraphenylene vinylene) reveal the nature of the excitonic bands in PPV oligomers.

scholarly journals Ab initio quantum-chemical computations of the absorption cross sections of HgX2 and HgXY (X, Y = Cl, Br, and I): molecules of interest in the Earth's atmosphere

2019 ◽  
Vol 21 (1) ◽  
pp. 455-467 ◽  
Author(s):  
Sebastian P. Sitkiewicz ◽  
Daniel Rivero ◽  
Josep M. Oliva-Enrich ◽  
Alfonso Saiz-Lopez ◽  
Daniel Roca-Sanjuán
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Cross Sections ◽  
Quantum Chemical ◽  
Electronic States ◽  
Absorption Cross ◽  
Spectrum Range ◽  
Mercury Halides ◽  
Quantum Chemical Computations ◽  
Structure Properties

The electronic-structure properties of the low-lying electronic states and the absorption cross sections of mercury halides have been determined within the UV-vis spectrum range (170 nm ≤ λphoton ≤ 600 nm).

Ab initio quantum–chemical computations of the electronic states in HgBr2 and IBr: Molecules of interest on the Earth’s atmosphere

2016 ◽  
Vol 145 (24) ◽  
pp. 244304 ◽  
Author(s):  
Sebastian P. Sitkiewicz ◽  
Josep M. Oliva ◽  
Juan Z. Dávalos ◽  
Rafael Notario ◽  
Alfonso Saiz–Lopez ◽  
...  
Keyword(s):  
Ab Initio ◽  
Quantum Chemical ◽  
Electronic States ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere ◽  
Quantum Chemical Computations

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.

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