scholarly journals The effect of ionic composition on acoustic phonon speeds in hybrid perovskites from Brillouin spectroscopy and density functional theory

2018 ◽  
Vol 6 (15) ◽  
pp. 3861-3868 ◽  
Author(s):  
Irina V. Kabakova ◽  
Ido Azuri ◽  
Zhuoying Chen ◽  
Pabitra K. Nayak ◽  
Henry J. Snaith ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Acoustic Phonon ◽  
Density Functional ◽  
Ionic Composition ◽  
Functional Theory ◽  
Brillouin Spectroscopy ◽  
The Impact

The impact of A and X site substitution on acoustic phonon speeds in hybrid perovskites with ABX3 stoichiometry is studied.

scholarly journals An Evaluation of the Impact of the Amount of Potassium Hydroxide on the Porous Structure Development of Activated Carbons

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2045
Author(s):  
Mirosław Kwiatkowski ◽  
Elżbieta Broniek ◽  
Vanessa Fierro ◽  
Alain Celzard
Keyword(s):  
Density Functional Theory ◽  
Porous Structure ◽  
Potassium Hydroxide ◽  
Density Functional ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Appropriate Technology ◽  
Functional Theory ◽  
Homogeneous Surface ◽  
The Impact

This paper presents the results of an evaluation of the impact of the amount of potassium hydroxide on the obtained porous structure of the activated carbons derived from the shells of pistachios, hazelnuts, and pecans by carbonization and subsequent chemical activation with potassium hydroxide by different adsorption methods: Brunauer–Emmett–Teller, Dubinin–Raduskevich, the new numerical clustering-based adsorption analysis, Quenched Solid Density Functional Theory, and 2D-Non-linear Density Functional Theory for Heterogeneous Surfaces, applied to nitrogen adsorption isotherms at −196 °C. Based on the conducted research, a significant potential for the production of activated carbons from waste materials, such as nut shells, has been demonstrated. All the activated carbons obtained in the present study at the activator/char mass ratio R = 4 exhibited the most developed porous structure, and thus very good adsorption properties. However, activated carbons obtained from pecan shells deserve special attention, as they were characterized by the most homogeneous surface among all the samples analyzed, i.e., by a very desirable feature in most adsorption processes. The paper demonstrates the necessity of using different methods to analyze the porous structure of activated carbons in order to obtain a complete picture of the studied texture. This is because only a full spectrum of information allows for correctly selecting the appropriate technology and conditions for the production of activated carbons dedicated to specific industrial applications. As shown in this work, relying only on the simplest methods of adsorption isotherm analysis can lead to erroneous conclusions due to lack of complete information on the analyzed porous structure. This work thus also explains how and why the usual characterizations of the porous structure of activated carbons derived from lignocellulosic biomass should not be taken at face value. On the contrary, it is advisable to cross reference several models to get a precise idea of the adsorbent properties of these materials, and therefore to propose the most suitable production technology, as well as the conditions of the preparation process.

scholarly journals Carrier-mediated ferromagnetism in two-dimensional PtS2

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 952-957 ◽  
Author(s):  
Konstantina Iordanidou ◽  
Michel Houssa ◽  
Clas Persson
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Hole Doping ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Impact

Using first principles calculations based on density functional theory the impact of hole doping on the magnetic and electronic properties of two dimensional PtS2 is studied.

The impact of cation–π, anion–π, and CH–π interactions on the excited-state intramolecular proton transfer of 1,4-dihydroxyanthraquinone

2021 ◽  
Author(s):  
Asiyeh Shahraki ◽  
Ali Ebrahimi ◽  
Shiva Rezazadeh ◽  
Roya Behazin
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Photophysical Properties ◽  
Intramolecular Proton Transfer ◽  
Time Dependent ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The Impact ◽  
Dependent Density

The impact of ion-π interactions on the photophysical properties of quinizarin have been investigated using the density functional theory and time-dependent density functional theory at the M06-2X/6-311++G(d,p) level in the gas phase and solution.

Fast computation of DFT nuclear gradient with multiresolution*This article is dedicated to Dr. Russell J. Boyd for his distinguished career in chemical research.

2011 ◽  
Vol 89 (6) ◽  
pp. 657-662 ◽  
Author(s):  
Nicholas J. Russ ◽  
Chun-min Chang ◽  
Jing Kong
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Computational Cost ◽  
Basis Sets ◽  
Local Spin Density Approximation ◽  
Functional Theory ◽  
Exchange Correlation ◽  
The Impact

We present an efficient algorithm for evaluating the exchange-correlation contribution to the nuclear gradients of density-functional theory calculation within the local spin-density approximation. The algorithm is an extension of the multiresolution exchange-correlation (mrXC) method, which treats smooth and compact parts of the electron density separately. The nuclear gradient of the smooth density is calculated on the even-spaced grid while the compact part of the density is handled on the normal atom-centered grid (ACG). The overall formulism is still formally based on the ACG, and thus does not change the results of the existing ACG-based algorithms for all-electron density-functional theory (DFT) calculations. The variation of the positions and weights of ACG owing to the nuclear perturbation is also handled rigorously. Benchmark calculations with different basis sets and sizes of ACG show that mrXC reduces the computational cost by several times without loss of accuracy. It also lessens the impact on the CPU time when the size of the ACG is increased.

scholarly journals Some Trinitroazetidine Isomers - A DFT Treatment

2021 ◽  
pp. 85-98
Author(s):  
Lemi Türker
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Spectral Properties ◽  
Density Functional ◽  
High Energy ◽  
Explosive Material ◽  
Functional Theory ◽  
The Impact

The present study considers some trinitroazetidine isomers within the realm of density functional theory (B3LYP/6-311++G(d,p)). One of the isomers considered is 1,3,3-trinitroazetidine (TNAZ) which is the well known insensitive high energy explosive material. Various structural, energetic, quantum chemical and spectral properties of the isomers have been harvested and discussed. Some of the isomers have nitramine bonds and some possess only C-NO2 bonds. The results indicate that the nitramine moiety somewhat destabilizes the structure electronically but increases the impact insensitivity.

Density functional theory study on the reaction of triazol-3-one with nitronium: direct nitration versus acidic group-induced nitration

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25183-25191 ◽  
Author(s):  
Kuan Wang ◽  
Jian-Gang Chen ◽  
Bozhou Wang ◽  
Fengyi Liu ◽  
Zhao-Tie Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Catalytic Effect ◽  
Acid Group ◽  
Induction Effect ◽  
Density Functional Theory Study ◽  
Acidic Group ◽  
Functional Theory ◽  
The Impact

Herein, an unexpected induction effect derived from the coexisted acid group (NO3− and/or HSO4−) was proposed. The impact of the induction effect and the resulted enhanced catalytic effect on the nitration of TO was systematically demonstrated.

scholarly journals Aqueous solvation of the chloride ion revisited with density functional theory: impact of correlation and exchange approximations

2020 ◽  
Vol 22 (19) ◽  
pp. 10666-10675 ◽  
Author(s):  
Mark DelloStritto ◽  
Jianhang Xu ◽  
Xifan Wu ◽  
Michael L. Klein
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chloride Ion ◽  
Functional Theory ◽  
Aqueous Solvation ◽  
Aqueous Chloride ◽  
Exact Exchange ◽  
The Impact ◽  
Exchange And Correlation

Aqueous chloride is simulated using PBE-D3, PBE0-D3, and SCAN to investigate the impact of exchange and correlation approximations; we find the exact exchange fraction strongly impacts the energetics and polarizability of solvated chloride.

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