Density Functional Study of Physical and Chemical Properties of Nano Size Boron Clusters: Bn (n = 1320)

2009 ◽  
Vol 22 (4) ◽  
pp. 380-388 ◽  
Author(s):  
Murat Atis ◽  
Cem Ozdosan ◽  
Ziya B. Guvenc
Química Nova ◽  
2021 ◽  
Author(s):  
Kamila Ody ◽  
João Jesus ◽  
Carlos Cava ◽  
Anderson Albuquerque ◽  
Ary Maia ◽  
...  

ASSESSMENT OF THE ELECTRONIC STRUCTURE OF THE MONOCLINIC PHASE OF NIOBIUM OXIDE BASED ON THE USE OF DIFFERENT DENSITY FUNCTIONALS. Niobium oxides, Nb2O5, are considered semiconductor materials with very attractive physical and chemical properties for applications in many areas, such as catalysis, sensors, medical, aerospace, etc. Especially, the characterization of Nb2O5-based nanostructures with monoclinic structure has received much attention in recent years. However, despite the great importance of this system, some of its fundamentals properties are still not fully understood. Hence, this work aims to apply the theoretical methodologies through Density Functional Theory (DFT) calculations in periodic models based on the use of different density functionals (like B1WC, B3PW, B3LYP, PBE0, PBESOL0, SOGGAXC, and WC1LYP) to investigate the physical and chemical properties of the monoclinic structure of Nb2O5. The band structures, energy bandgap, density of state, and vibrational properties, as well as order-disorder effects on the monoclinic structure of Nb2O5 are investigated in this study. Our theoretical results show a better agreement with experimental data for the B3LYP functional and hence lead to new perspectives on the deeper physicochemical understanding of the monoclinic Nb2O5. From these computational tools, it is possible to unravel the relations between structure and properties, which may contribute to the future development of new devices and applications based on these materials.


2020 ◽  
Vol 6 (2) ◽  
pp. 114-119
Author(s):  
Alaa Alnaimat ◽  
Intesar Aljamaeen

In principle, nanoscience focus on the understanding of the structure, physical and chemical properties of nano size objects. Nanoscience and nanotechnology are both recent and active ongoing branch of science includes multi interdisciplinary sciences. On the other hand, nanotechnology considered as the invested outcomes of the obtained fundamental knowledge about nano objects in various commercial, industrial, environmental and medical sectors. All nano scale matters regardless of their nature referred to as nano-objects were the prefix ‘nano’ mean one millionth of millimeter size. Due to their nano size and high surface area, metal nanoparticles exhibits unique and novel physical and chemical properties compared to their macro scale counterparts. They are considered as very interesting and popular antimicrobial agent with wide spectrum activity against the variety of pathogenic bacteria and fungi. Three main methods were routinely used for metal nanoparticles formation that are chemical, physical and biological approaches. As eco-friendly, cheap and safe synthesis approach without the use of toxic chemicals and free of resulted hazardous byproducts several extracellular and intracellular biological methods using bacteria, fungi, plants or their extracts were reported that known collectively as green nanotechnology


2017 ◽  
Vol 19 (23) ◽  
pp. 15484-15502 ◽  
Author(s):  
Anderson S. Chaves ◽  
Maurício J. Piotrowski ◽  
Juarez L. F. Da Silva

Subnanometric transition-metal (TM) clusters have attracted great attention due to their unexpected physical and chemical properties, leastwise compared to their bulk counterparts.


2017 ◽  
Vol 46 (2) ◽  
pp. 529-538 ◽  
Author(s):  
Yunguo Li ◽  
Pavel A. Korzhavyi

The electronic structure and chemical bonding of Cu(i) compounds with O and/or H are investigated using ab initio calculations based on density functional theory.


Author(s):  
Dejan Zagorac ◽  
Jelena Zagorac ◽  
J. Christian Schön ◽  
Nemanja Stojanović ◽  
Branko Matović

The range of feasible ZnO/ZnS polytypes has been explored, predicting alternative structural arrangements compared with previously suggested or observed structural forms of ZnO/ZnS compounds, including bulk crystal structures, various nanostructures, heterostructures and heterojunctions. All calculations were performed ab initio using density functional theory–local density approximation and hybrid Heyd–Scuseria–Ernzerhof functionals. Specifically, pure ZnO and ZnS compounds and mixed ZnO1–x S x compounds (x = 0.20, 0.25, 0.33, 0.50, 0.60, 0.66 and 0.75) are investigated and a multitude of possible stable polytypes for ZnO/ZnS compounds creating new possibilities for synthesis of new materials with improved physical and chemical properties are identified.


1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.


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