scholarly journals Ab Initio Molecular Dynamics of CdSe Quantum-Dot-Doped Glasses

2020 ◽  
Vol 142 (8) ◽  
pp. 3905-3912
Author(s):  
Wenke Li ◽  
Xiujian Zhao ◽  
Chao Liu ◽  
François-Xavier Coudert
2019 ◽  
Author(s):  
Wenke Li ◽  
Xiujian Zhao ◽  
Chao Liu ◽  
François-Xavier Coudert

<div> <div> <div> <p>We have probed the local atomic structure of the interfacial structure between the CdSe quantum dots (QDs) and sodium silicate glass matrix. Using ab initio molecular dynamics simulations, we determined the structural properties and bond length, in excellent agreement with previous experimental observations. Based on analysis of radial distribution functions, coordination environment and ring structures, we demonstrate that huge structure reconstruction occurs at the interface between the CdSe QDs and the glass matrix. The incorporation of the CdSe QDs disrupts the Na-O bonds, while stronger SiO4 tetrahedra are reformed. The existence of the glass matrix breaks the stable 4-member (4MR) and 6-member (6MR) of Cd-Se rings, and we observe a disassociated Cd atom dissolved in the glass matrix. Besides, the formation of Se-Na and Cd-O linkages is observed at the CdSe QDs/glass interface. These results significantly extend our understanding of the interfacial structure of the CdSe QDs doped glasses, and provide physical and chemical insight into the possible defect structure origin of CdSe QDs, of interest to the fabrication of the highly luminescent CdSe QDs doped glasses. </p> </div> </div> </div>


2019 ◽  
Author(s):  
Wenke Li ◽  
Xiujian Zhao ◽  
Chao Liu ◽  
François-Xavier Coudert

<div> <div> <div> <p>We have probed the local atomic structure of the interfacial structure between the CdSe quantum dots (QDs) and sodium silicate glass matrix. Using ab initio molecular dynamics simulations, we determined the structural properties and bond length, in excellent agreement with previous experimental observations. Based on analysis of radial distribution functions, coordination environment and ring structures, we demonstrate that huge structure reconstruction occurs at the interface between the CdSe QDs and the glass matrix. The incorporation of the CdSe QDs disrupts the Na-O bonds, while stronger SiO4 tetrahedra are reformed. The existence of the glass matrix breaks the stable 4-member (4MR) and 6-member (6MR) of Cd-Se rings, and we observe a disassociated Cd atom dissolved in the glass matrix. Besides, the formation of Se-Na and Cd-O linkages is observed at the CdSe QDs/glass interface. These results significantly extend our understanding of the interfacial structure of the CdSe QDs doped glasses, and provide physical and chemical insight into the possible defect structure origin of CdSe QDs, of interest to the fabrication of the highly luminescent CdSe QDs doped glasses. </p> </div> </div> </div>


2019 ◽  
Author(s):  
Liqun Cao ◽  
Jinzhe Zeng ◽  
Mingyuan Xu ◽  
Chih-Hao Chin ◽  
Tong Zhu ◽  
...  

Combustion is a kind of important reaction that affects people's daily lives and the development of aerospace. Exploring the reaction mechanism contributes to the understanding of combustion and the more efficient use of fuels. Ab initio quantum mechanical (QM) calculation is precise but limited by its computational time for large-scale systems. In order to carry out reactive molecular dynamics (MD) simulation for combustion accurately and quickly, we develop the MFCC-combustion method in this study, which calculates the interaction between atoms using QM method at the level of MN15/6-31G(d). Each molecule in systems is treated as a fragment, and when the distance between any two atoms in different molecules is greater than 3.5 Å, a new fragment involved two molecules is produced in order to consider the two-body interaction. The deviations of MFCC-combustion from full system calculations are within a few kcal/mol, and the result clearly shows that the calculated energies of the different systems using MFCC-combustion are close to converging after the distance thresholds are larger than 3.5 Å for the two-body QM interactions. The methane combustion was studied with the MFCC-combustion method to explore the combustion mechanism of the methane-oxygen system.


2021 ◽  
Vol 22 (9) ◽  
pp. 4378
Author(s):  
Anna Helena Mazurek ◽  
Łukasz Szeleszczuk ◽  
Dariusz Maciej Pisklak

This review focuses on a combination of ab initio molecular dynamics (aiMD) and NMR parameters calculations using quantum mechanical methods. The advantages of such an approach in comparison to the commonly applied computations for the structures optimized at 0 K are presented. This article was designed as a convenient overview of the applied parameters such as the aiMD type, DFT functional, time step, or total simulation time, as well as examples of previously studied systems. From the analysis of the published works describing the applications of such combinations, it was concluded that including fast, small-amplitude motions through aiMD has a noticeable effect on the accuracy of NMR parameters calculations.


ACS Omega ◽  
2021 ◽  
Author(s):  
Khagendra Baral ◽  
Saro San ◽  
Ridwan Sakidja ◽  
Adrien Couet ◽  
Kumar Sridharan ◽  
...  

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