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.

Ab initio and DFT analysis of the low-lying electronic states of metal dihalides: quantum chemical calculations on the neutral BrMCl (M = Cu, Ag, Au)

2013 ◽  
Vol 15 (25) ◽  
pp. 10151
Author(s):  
Michiko Atsumi ◽  
Roland Lindh ◽  
Leticia González ◽  
Christophe Gourlaouen ◽  
Chantal Daniel
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Electronic States ◽  
Ab Initio And Dft

COMPARISON OF PHOTOELECTRON SPECTRA OF ${\rm Cu}_n^-$, ${\rm Ag}_n^-$, AND ${\rm Na}_n^-$: MOLECULAR ORBITALS VERSUS ELECTRONIC SHELLS

1996 ◽  
Vol 03 (01) ◽  
pp. 399-403 ◽  
Author(s):  
G. GANTEFÖR ◽  
H. HANDSCHUH ◽  
H. MÖLLER ◽  
CHIA-YEN CHA ◽  
P.S. BECHTHOLD ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Shell Model ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Electronic States ◽  
Molecular Orbitals ◽  
Photoelectron Spectra

The photoelectron spectra of [Formula: see text] clusters are compared to the results of quantmn-chemical ab-initio calculations (n=2-9) and to the predictions of the shell model. The shell model yields qualitative assignments of the dominant features in the spectra to photoemission from occupied electronic shells. These correspond to the exact quantitative assignments to transitions into various electronic states of the neutral clusters according to the quantum-chemical calculations. The photoelectron spectra of [Formula: see text] and [Formula: see text] clusters exhibit certain similarities to the Ag data in agreement with the basic idea of the shell model.

Ab initio investigation of the ground and excited states of RuO+,0,− and their reaction with water

2020 ◽  
Vol 22 (28) ◽  
pp. 16072-16079 ◽  
Author(s):  
Isuru R. Ariyarathna ◽  
Nuno M. S. Almeida ◽  
Evangelos Miliordos
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Excited States ◽  
Quantum Chemical ◽  
Electronic States ◽  
Reaction With Water ◽  
High Level

High-level quantum chemical calculations reveal the electronic structure of low-lying electronic states of RuO0,±, and that the anion can activate the OH bond of water more readily.

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.

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

VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

2002 ◽  
Vol 09 (01) ◽  
pp. 153-158 ◽  
Author(s):  
WEIDONG ZHOU ◽  
D. P. SECCOMBE ◽  
R. Y. L. CHIM ◽  
R. P. TUCKETT
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Ground State ◽  
Lower Energy ◽  
Lone Pair ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Highest Occupied Molecular Orbital ◽  
Impulsive Model ◽  
Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

scholarly journals Geometric and energetic data from quantum chemical calculations of halobenzenes and xylenes

2020 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Software Package ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Basis Set ◽  
Chemical Calculation ◽  
Custom Made

<p>This article presents theoretical data on geometric and energetic features of halobenzenes and xylenes. Data were obtained from <i>ab initio</i> geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</p>

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