scholarly journals First principles study of surface properties and oxygen adsorption on the surface of Al3Ti intermetallic alloys

RSC Advances ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 1752-1758 ◽  
Author(s):  
Yang Zhou ◽  
Huihui Xiong ◽  
Yanhong Yin ◽  
Shengwen Zhong

The density functional theory (DFT) method was applied to study the structural, electronic and surface properties of low-index Al3Ti intermetallic materials.

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.


Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...


2020 ◽  
Author(s):  
Saeedeh Mohammadi ◽  
Mohammad Esmailpour ◽  
Mina Mohammadi

Abstract This paper is a new step in helping the treatment of coronavirus by improving the performance of chloroquine drug. For this purpose, we propose a complex of chloroquine drug with graphene nanoribbon (GNR) scheme. We compute the structural and electrical properties and absorption of chloroquine (C18H26ClN3) and GNR complex using the density functional theory (DFT) method. By creating a drug and GNR complex, the density of states of electrons increases and the energy gap decreases compared to the chloroquine. Also, using absorption calculations and spectrums such as infrared and UV-Vis spectra, we showed that GNR is a suitable structure for creating chloroquine drug complex. Our results show that the dipole moment, global softness and electrophilicity for the drug complex increases compared to the non-complex state. Our calculations can be useful for increasing performance and reducing the side effects of chloroquine, and thus can be effective in treating coronavirus.


RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25900-25911 ◽  
Author(s):  
Esmaeil Pakizeh ◽  
Jaafar Jalilian ◽  
Mahnaz Mohammadi

In this study, based on the density functional theory and semi-classical Boltzmann transport theory, we investigated the structural, thermoelectric, optical and phononic properties of the Fe2ZrP compound.


Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 359 ◽  
Author(s):  
Hanwei Li ◽  
Mingliang Luo ◽  
Guohong Tao ◽  
Song Qin

Computational investigations on the bisphospholanoethane (BPE)-ligated Cu-catalyzed enantioselective addition of enynes to ketones were performed with the density functional theory (DFT) method. Two BPE-mesitylcopper (CuMes) catalysts, BPE-CuMes and (S,S)-Ph-BPE–CuMes, were employed to probe the reaction mechanism with the emphasis on stereoselectivity. The calculations on the BPE-CuMes system indicate that the active metallized enyne intermediate acts as the catalyst for the catalytic cycle. The catalytic cycle involves two steps: (1) ketone addition to the alkene moiety of the metallized enyne; and (2) metallization of the enyne followed by the release of product with the recovery of the active metallized enyne intermediate. The first step accounts for the distribution of the products, and therefore is the stereo-controlling step in chiral systems. In the chiral (S,S)-Ph-BPE–CuMes system, the steric hindrance is vital for the distribution of products and responsible for the stereoselectivity of this reaction. The steric hindrance between the phenyl ring of the two substrates and groups at the chiral centers in the ligand skeleton is identified as the original of the stereoselectivity for the titled reaction.


2010 ◽  
Vol 09 (supp01) ◽  
pp. 65-75 ◽  
Author(s):  
JING LI ◽  
WAN-YI JIANG

The trimethylamine-catalyzed Baylis–Hillman reaction of formaldehyde and vinylaldehyde has been studied with the density functional theory (DFT) method of B3LYP/6-31+G(d,p). In the gas phase, the reaction involves an amine–formaldehyde–vinylaldehyde trimolecular addition transition structure followed by rate-determining intramolecular 1,3-hydrogen shift. When a bulk solvent effect of water was considered with conductor-like polarizable continuum model (CPCM), the reaction was found to follow the sequence of Michael-addition of amine to vinylaldehyde (step 1), addition of formaldehyde (step 2), and 1,3-hydrogen shift (step 3), with the 1,3-hydrogen shift as rate-determining. The overall reaction barrier is significantly reduced. When a molecule of water is involved in the reaction, the 1,3-hydrogen shift is significantly promoted so that the rate-determining step becomes the C–C bond formation. The calculated overall reaction barrier is in agreement with experimental observations.


2010 ◽  
Vol 25 (12) ◽  
pp. 2317-2324 ◽  
Author(s):  
Hui-Yuan Wang ◽  
Wen-Ping Si ◽  
Shi-Long Li ◽  
Nan Zhang ◽  
Qi-Chuan Jiang

The formation enthalpy, electronic structures, and elastic moduli of the intermetallic compound Ti5Si3 with substitutions Zr, V, Nb, and Cr are investigated by using first-principles methods based on the density-functional theory. Our calculation shows that the site occupancy behaviors of alloying elements in Ti5Si3, determined by their atom radius, are consistent with the available experimental observations. Furthermore, using the Voigt–Reuss–Hill (VRH) approximation method, we obtained the bulk modulus B, shear modulus G, and the Young’s modulus E. Among these four substitutions, the V, Nb, and Cr substitutions can improve the ductility of Ti5Si3 effectively, while Zr substitution has little effect on the elastic properties of Ti5Si3. The elastic property variations of Ti5Si3 due to different substitutions are found to be correlated with the Me4d–Me4d antibonding and the strengthened Me4d–Si bonding in the solids.


RSC Advances ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 7941-7949 ◽  
Author(s):  
Naeem Shahzad ◽  
Akhtar Hussain ◽  
Naeem Mustafa ◽  
Nisar Ali ◽  
Mohammed Benali Kanoun ◽  
...  

Adsorption and dissociation mechanisms of H2S on a TiO2(001) surface were elucidated using first principles calculation based on the density functional theory.


2019 ◽  
Vol 489 (1) ◽  
pp. 62-64 ◽  
Author(s):  
D. P. Krylov ◽  
A. B. Kuznetsov

Temperature relations of b-factors for 18O/16O substitutions in TiO2 polymorphs have been determined using the density functional theory (DFT): 1000lnbrt(18O/16O) = 6,93039x - 0,08158x2 + 0,00116x3 + 0,08305*P, 1000lnbant(18O/16O) = 7,34275x - 0,09906x2 + 0,00153x3 + 0,08027*P, 1000lnbbrk(18O/16O) = 7,19088x - 009157x2 + 0,00139x3 + 0,07601*P, x = 106/T(K)2, P - pressure (GPa). The relations can be applied for isotope thermometry if combined with -factors of coexisting phases.


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