Density functional and ab initio study of the ketene and methylketene radical cations

1998 ◽  
Vol 109 (20) ◽  
pp. 8953-8958 ◽  
Author(s):  
Ming-Bao Huang ◽  
Zhi-Xiang Wang
2003 ◽  
Vol 68 (12) ◽  
pp. 2322-2334 ◽  
Author(s):  
Robert Vianello ◽  
Zvonimir B. Maksić

The electronic and energetic properties of thymine (1) and 2-thiothymine (2) and their neutral and positively charged radicals are considered by a combined ab initio and density functional theory approach. It is conclusively shown that ionization of 1 and 2 greatly facilitates deprotonation of the formed radical cations thus making the proton transfer between charged and neutral precursor species thermodynamically favourable. The adiabatic ionization potential of 1 and 2 are analysed. It appears that ADIP(1) is larger than ADIP(2) by 10 kcal/mol, because of greater stability of the highest occupied molecular orbital (HOMO) of the former. It is also shown beyond any doubt that the spin density in neutral and cationic radical of 2 is almost exclusively placed on the σ-3p AO of sulfur implying that these two systems represent rather rare sigma-radicals. In contrast, the spin density of radicals of 1 is distributed over their π-network.


Author(s):  
Banjo Semire ◽  
Isaiah Ajibade Adejoro ◽  
Olusegun Ayobami Odunola

In this paper, we theoretically studied the geometries, stabilities, electronic and thermodynamic properties of bridged bithiophene S-oxide (BTO-X) derivates (with X = BH2, SiH2, S, S=O, and O) by using semi-empirical methods, ab-initio, and Density functional theory. The geometries and thermodynamic parameters calculated by PM3 were in good agreement with that of B3LYP/6-31G(d). The bandgap calculated by B3LYP/6-31G(d) ranged from 3.94eV (BTO-O)-3.16eV (BTO-BH2). The absorption λmax calculated suing B3LYP/6-31G(d) shifted to longer wavelength with X=BH2, SiH2, and S=O due to enhancement of π-conjugated system whereas, BTO-S and BTO-O shifted to shorter wavelengths as compared to dimmer thiophene S-oxide (2TO).


RSC Advances ◽  
2020 ◽  
Vol 10 (61) ◽  
pp. 37142-37152
Author(s):  
Yi X. Wang ◽  
Ying Y. Liu ◽  
Zheng X. Yan ◽  
W. Liu ◽  
Jian B. Gu

The phase stabilities, elastic anisotropies, and thermal conductivities of ReB2 diborides under ambient conditions have been investigated by using density functional theory calculations.


2016 ◽  
Vol 30 (23) ◽  
pp. 1650291 ◽  
Author(s):  
D. E. Aimouch ◽  
S. Meskine ◽  
R. Hayn ◽  
A. Zaoui ◽  
A. Boukortt

We present the results of ab initio calculations of K-doped ZnO in the wurtzite structure using a supercell of 32 atoms and density functional theory. A complete analysis of its electronic, optical and magnetic properties is provided. The local spin density approximation (LSDA) has been used to analyze the density of states and to understand the K influence at different concentration values. The material is revealed to become a [Formula: see text]-type doped semiconductor. The optical constant or refractive index, the dielectric function, and the absorption coefficient were determined and show a good agreement with available experimental data. Potassium doping leads to an absorption peak at about 380 nm. That peak might improve the absorption characteristics of ZnO for solar cell or optical applications.


2020 ◽  
Vol 22 (33) ◽  
pp. 18423-18434
Author(s):  
Malladi Srikanth ◽  
Mailde S. Ozório ◽  
Juarez L. F. Da Silva

Optical and dielectric properties, and energetic stability orders of black phase of perovskites and yellow phase of iodoplumbates have been studied using density functional theory; where the optical dielectric constant varies with the polymorphic phase and nature of cation.


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