scholarly journals Electronic Structure with Dipole Moment and Rovibrational Calculation of Cadmium Chalcogenide Molecules CdX (X = Se, Te)

ACS Omega ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 920-931
Author(s):  
Khalil Badreddine ◽  
Mahmoud Korek
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
Cadmium Chalcogenide

scholarly journals Determining Partial Atomic Charges for Liquid Water: Assessing Electronic Structure and Charge Models

2020 ◽  
Author(s):  
Bowen Han ◽  
Christine Isborn ◽  
Liang Shi
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
Charge Transfer ◽  
Liquid Water ◽  
Quantum Chemical ◽  
Water Dimer ◽  
Atomic Charges ◽  
Molecular Dipole ◽  
Molecular Dipole Moment ◽  
Partial Atomic Charges

Partial atomic charges provide an intuitive and efficient way to describe the charge distribution and the resulting intermolecular electrostatic interactions in liquid water. Many charge models exist and it is unclear which model provides the best assignment of partial atomic charges in response to the local molecular environment. In this work, we systematically scrutinize various electronic structure methods and charge models (Mulliken, Natural Population Analysis, CHelpG, RESP, Hirshfeld, Iterative Hirshfeld, and Bader) by evaluating their performance in predicting the dipole moments of isolated water, water clusters, and liquid water as well as charge transfer in the water dimer and liquid water. Although none of the seven charge models is capable of fully capturing the dipole moment increase from isolated water (1.85 D) to liquid water (about 2.9 D), the Iterative Hirshfeld method performs best for liquid water, reproducing its experimental average molecular dipole moment, yielding a reasonable amount of intermolecular charge transfer, and showing modest sensitivity to the local water environment. The performance of the charge model is dependent on the choice of the density functional and the quantum treatment of the environment. The computed molecular dipole moment of water generally increases with the percentage of the exact Hartree-Fock exchange in the functional, whereas the amount of charge transfer between molecules decreases. For liquid water, including two full solvation shells of surrounding water molecules (within about 5.5 A of the central water) in the quantum-chemical calculation converges the charges of the central water molecule. Our final pragmatic quantum-chemical charge assigning protocol for liquid water is the Iterative Hirshfeld method with M06-HF/aug-cc-pVDZ and a quantum region cutoff radius of 5.5 A.<br>

scholarly journals Theoretical electronic structure with rovibrational and dipole moment calculation of SiN Molecule

2019 ◽  
Vol 1258 ◽  
pp. 012034
Author(s):  
Nayla El-Kork ◽  
Salman Mahmoud ◽  
Mikhael Bechelany ◽  
Philippe Miele ◽  
Mahmoud Korek
Keyword(s):  
Electronic Structure ◽  
Dipole Moment

Electronic structure of POPC phospholipids under constant electric field

2017 ◽  
Vol 31 (22) ◽  
pp. 1750157
Author(s):  
Jaciéli Evangelho de Figueiredo ◽  
Leandro Barros da Silva
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
External Field ◽  
Electric Field ◽  
Electric Fields ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Constant Electric Field ◽  
Ab Initio Study ◽  
Electronic And Structural Properties

We report in the present paper an ab initio study on the electronic and structural properties of phospholipidic membranes under the influence of electric fields. We show that the external field alters the charge distribution of the molecule leading to a modification in the electric dipole moment. The torque on the phospholipid may then cause a transmembranar stress, which by its turn, weakens the membrane allowing to the formation of a pore.

scholarly journals Determining Partial Atomic Charges for Liquid Water: Assessing Electronic Structure and Charge Models

2020 ◽  
Author(s):  
Bowen Han ◽  
Christine Isborn ◽  
Liang Shi
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
Charge Transfer ◽  
Liquid Water ◽  
Quantum Chemical ◽  
Water Dimer ◽  
Atomic Charges ◽  
Molecular Dipole ◽  
Molecular Dipole Moment ◽  
Partial Atomic Charges

Partial atomic charges provide an intuitive and efficient way to describe the charge distribution and the resulting intermolecular electrostatic interactions in liquid water. Many charge models exist and it is unclear which model provides the best assignment of partial atomic charges in response to the local molecular environment. In this work, we systematically scrutinize various electronic structure methods and charge models (Mulliken, Natural Population Analysis, CHelpG, RESP, Hirshfeld, Iterative Hirshfeld, and Bader) by evaluating their performance in predicting the dipole moments of isolated water, water clusters, and liquid water as well as charge transfer in the water dimer and liquid water. Although none of the seven charge models is capable of fully capturing the dipole moment increase from isolated water (1.85 D) to liquid water (about 2.9 D), the Iterative Hirshfeld method performs best for liquid water, reproducing its experimental average molecular dipole moment, yielding a reasonable amount of intermolecular charge transfer, and showing modest sensitivity to the local water environment. The performance of the charge model is dependent on the choice of the density functional and the quantum treatment of the environment. The computed molecular dipole moment of water generally increases with the percentage of the exact Hartree-Fock exchange in the functional, whereas the amount of charge transfer between molecules decreases. For liquid water, including two full solvation shells of surrounding water molecules (within about 5.5 A of the central water) in the quantum-chemical calculation converges the charges of the central water molecule. Our final pragmatic quantum-chemical charge assigning protocol for liquid water is the Iterative Hirshfeld method with M06-HF/aug-cc-pVDZ and a quantum region cutoff radius of 5.5 A.<br>

Electronic absorption spectrum and π-electronic structure of cryptocyanine

1980 ◽  
Vol 45 (2) ◽  
pp. 307-320 ◽  
Author(s):  
Miloš Titz ◽  
Antonín Novák ◽  
Viktor Řehák
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Dipole Moment ◽  
Excited State ◽  
Absorption Band ◽  
Electronic Absorption ◽  
Quantum Chemical ◽  
Fluorescence Excitation ◽  
Real Geometry ◽  
Optimum Model

Absorption, fluorescence excitation and APF spectra of cryptocyanine have been measured. Dipole moment of the respective S1 excited state has been estimated from shifts of the marked maximum of the first absorption band in various solvents. On the basis of quantum-chemical calculations carried out by the PPP method in the approximation of quasi-real geometry we have received the optimum model of π-electronic structure of the cryptocyanine molecule and therefrom the theoretical electronic singlet spectrum inclusive character of the S0 - S1 transition.

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