Catalyic conversion of hydrocarbons in zeolites from first principles

2002 ◽  
Vol 74 (11) ◽  
pp. 2097-2100 ◽  
Author(s):  
Ľubomír Benco ◽  
Thomas Demuth ◽  
François Hutschka

The application of the density functional techniques to processes of the conversion of hydrocarbons in zeolites has been reviewed. The conversion of hydrocarbons over zeolites is an important industrial process. The microscopic steps of the conversion, however, are still not satisfactorily understood. In order to examine reaction pathways, both static and molecular dynamics density functional theory (DFT) calculations have been performed. Simulated structural and spectral properties compare reasonably with experimental data. Comparison of energies of physisorption and chemisorption indicates possible reaction channel of the conversion through the chemisorption at the specific O-sites of the zeolite.

2017 ◽  
Vol 19 (15) ◽  
pp. 9912-9922 ◽  
Author(s):  
Sohag Biswas ◽  
Bhabani S. Mallik

The fluctuation dynamics of amine stretching frequencies, hydrogen bonds, dangling N–D bonds, and the orientation profile of the amine group of methylamine (MA) were investigated under ambient conditions by means of dispersion-corrected density functional theory-based first principles molecular dynamics (FPMD) simulations.


2014 ◽  
Vol 900 ◽  
pp. 203-208 ◽  
Author(s):  
Ting Ting Shao ◽  
Fu Chun Zhang ◽  
Wei Hu Zhang

The structural, electronic, and optical properties of rutile-type SnO2 are studied by plane-wave pseudopotential density functional theory (DFT) with GGA, LDA, B3LYP and PBE0 respectively. The computing results show that the band gap getting from PBE0 and B3LYP is much more consistent with the available experimental data than that from GGA and LDA, no matter what the latter use ultra-soft pseudopotential or norm conserving pseudopotential. However, the density of state, real part and imaginary part of dielectric function calculating from every type is basically similar in qualitative analysis.


2000 ◽  
Vol 640 ◽  
Author(s):  
Bernardo Barbiellini ◽  
Jan Kuriplach ◽  
Wolfgang Anwand ◽  
Gerhard Brauer

ABSTRACTPositron affinity calculations performed by a first-principles approach based on density functional theory reveal, contrary to many other semiconductors, that free positrons and positronium atoms can escape from SiC. It is found that the treatment of the electronpositron interaction plays a crucial role when calculating the annihilation characteristics. These characteristics originating from both valence and core electrons, combined with the corresponding measurements, yield a very useful tool for surface studies and point defect identification in the bulk. Calculations will be compared with available experimental data.


2015 ◽  
Vol 3 (42) ◽  
pp. 21351-21356 ◽  
Author(s):  
Lei Zhu ◽  
Qingzhong Xue ◽  
Xiaofang Li ◽  
Tiantian Wu ◽  
Yakang Jin ◽  
...  

Using the first-principles density functional theory (DFT) and molecular dynamics (MD) simulations, we investigate the He separation performance of a porous C2N monolayer synthesized recently.


2018 ◽  
Vol 6 (23) ◽  
pp. 11022-11036 ◽  
Author(s):  
Bohayra Mortazavi ◽  
Masoud Shahrokhi ◽  
Xiaoying Zhuang ◽  
Timon Rabczuk

We conducted density functional theory and classical molecular dynamics simulations to study the mechanical, thermal conductivity and stability, electronic and optical properties of single-layer boron–graphdiyne, a novel synthesized 2D material. Our first-principles results reveal the outstanding prospect of boron–graphdiyne as an anode material with ultrahigh charge capacities for Li, Na and Ca ions storage.


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