Stability, Structural and Electronic Properties of Indium Phosphide Wurtzite-Diamantane Molecules and Nanocrystals: A Density Functional Theory Study

2021 ◽  
Vol 69 ◽  
pp. 1-9
Author(s):  
Hamid A. Fayyadh
Keyword(s):  
Density Functional Theory ◽  
Raman Spectrum ◽  
Force Constant ◽  
Density Functional ◽  
Energy Gap ◽  
Spectroscopic Properties ◽  
Functional Theory ◽  
Bulk Energy ◽  
The Stability ◽  
Ir And Raman

The density functional theory is applied for examining the electronic structure and spectroscopic properties for InP wurtzite molecules and nanocrystals. In this paper we present calculations of the energy gap, bond lengths, IR and Raman spectrum, reduced mass and force constant. The results of the presented work showing that the InP’s energy gap was fluctuated about to experimental bulk energy gap (1.49 eV). Results of spectroscopic properties including IR and Raman spectrum, reduced mass and force constant as a function of frequency were in accordance with the provided experimental results. In addition, the study of the Gibbs free energy proved the stability phase of InP wurtzoids against transition to InP diamondoids structure.

STABLE STRUCTURES AND CHARACTERISTIC VIBRATIONAL SPECTRA OF TinOm(n = 2–4; m = 1–2n) CLUSTERS

2013 ◽  
Vol 12 (01) ◽  
pp. 1250094 ◽  
Author(s):  
HONGBO DU ◽  
YU JIA ◽  
RUI-QIN ZHANG
Keyword(s):  
Density Functional Theory ◽  
Raman Spectrum ◽  
Density Functional ◽  
Structure Property ◽  
Functional Theory ◽  
Experimental Identification ◽  
Structure Property Relationships ◽  
Method Of Density Functional ◽  
Ir And Raman ◽  
Stable Structures

The energetically favorable structures and characteristic infrared (IR) and Raman peaks of Ti n O m(n = 2–4, m ≤ 2n) clusters are obtained in this work using a B3LYP/6-311G(d) method of density functional theory (DFT). The structures with m < 2n compose of Ti atoms of lower numbers of coordination with O atoms, providing many dangling bonds which considerably enhance the reactivity compared with its bulk counterpart. Two- and three-coordinated O atoms present for m/n ≤ 1.5, whereas two- and also single-coordinated O atoms are found for m/n > 1.5. The Ti n O m(n = 2–4, m < 2n) clusters show strong IR peaks in the range of 600–1100 cm-1 and strong Raman peaks in the region of 300–800 cm-1, whereas both the IR and Raman spectrum peaks of the Ti n O m(n = 2–4, m = 2n) clusters are in the region of 700–1100 cm-1. The main Raman peak of the Ti n O m(m ≠ 2n) clusters is at a frequency considerably lower than that of the IR spectrum. Our results can help understand the structure-property relationships of the Ti n O m clusters and provide their characteristic spectroscope features for further experimental identification.

A DFT Study of Geometric Structure and Stability of Iron-Silicon Clusters

2014 ◽  
Vol 1048 ◽  
pp. 369-372
Author(s):  
Shuai Qin Yu ◽  
Hong Nan Ye
Keyword(s):  
Density Functional Theory ◽  
Geometric Structure ◽  
Density Functional ◽  
Energy Gap ◽  
Surface Site ◽  
Silicon Clusters ◽  
Lumo Energy ◽  
Functional Theory ◽  
The Stability ◽  
Homo Lumo

Geometric structures of Fe6-xSix(x=1-5) clusters have been systematically studied at the BPW91 level by density-functional theory (DFT). Calculated results show that the Fe atoms of the lowest-energy structures of Fe6-xSix clusters tend to go together, and Si atoms tend to occupy surface site bonding with iron atoms as many as possible. Further, we analyze the stability of the lowest-energy structures of Fe6-xSix clusters, and the corresponding results of the HOMO, LUMO as well as the HOMO-LUMO energy gap show that the Fe5Si and Fe4Si2 clusters have special stability.

Electronic and spectroscopic properties of Ge nanocrystals using diamondoid structures: A density functional theory study

2016 ◽  
Vol 30 (10) ◽  
pp. 1650058 ◽  
Author(s):  
Mudar Ahmed Abdulsattar
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Population Analysis ◽  
Size Variation ◽  
Building Blocks ◽  
Spectroscopic Properties ◽  
Longitudinal Optical ◽  
Functional Theory ◽  
Opposite Case

Energetically stable Ge diamondoids are used as building blocks to investigate Ge nanocrystal properties using density functional theory (DFT). Energy gap, HOMO and LUMO of Ge diamondoids vary according to confinement theory with shape fluctuations. Ge diamondoid vibrational force constants reach 2.18 mDyne/Å which is between that of bulk silicon and tin. Ge–Ge vibrational frequencies and reduced masses reach 357.47 cm[Formula: see text] and 41.93 amu, respectively, which are higher than the values of bulk Ge. Size variation of UV–Vis shows that the maximum optical peak moves from 163 nm to nearly 290 nm as the size of Ge diamondoids and molecules increases. The higher peak value approaches that of experimental Ge quantum dots at 300 nm. NMR spectra of Ge diamondoids are analyzed as a function of diamondoid sizes. Our results show that all investigated spectroscopic tools are sensitive to molecular or nanocrystals size. NMR is particularly good size indicator. Natural bond orbital (NBO) population analysis shows present diamondoid bondings differ from ideal [Formula: see text] bonding. The bonding for Ge valence orbitals is in the range [Formula: see text] depending on distance between Ge atom and diamondoid surface. Highest Ge diamondoids vibrational longitudinal optical (LO) mode is blue shifted with respect to experimental bulk value which is the opposite case for C and Si. H surface atom effects on electronic and vibrational properties are discussed.

scholarly journals Energetic and Electronic Properties of NH3, NO2 and SO2 Interacting with GaN Nanotube: A DFT Study

2021 ◽  
Author(s):  
Andrew A. J. Anchieta da Silva ◽  
Caio Vinícius Caetano ◽  
Silvete Guerini
Keyword(s):  
Density Functional Theory ◽  
Stability Analysis ◽  
Air Pollutants ◽  
Chemical Process ◽  
Density Functional ◽  
Energy Gap ◽  
Simulation Software ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The Stability

Abstract In this work, the interaction of GaN nanotube (GaNNT) with common air pollutants of industrialized cities, such as NH3, NO2 and SO2 in different configurations was studied. For this study, the single-walled (10,0) GaNNT was used. The analysis was done via the density functional theory implemented in the SIESTA simulation software. The analysis of the results shows that the air pollutants alter the properties of nanotubes when they interact with them. The stability analysis shows that the most stable configurations are those in which adsorption occurs through a chemical process. The systems remain semiconductors, but in the case of NO2 and SO2 molecules interacting with GaNNT, there was a significant reduction in the energy gap. Our results also indicate that GaNNT is a promising material to detect and remove NH3 and NO2 molecules from the environment, however it may be not applicable to detect or remove SO2, because the latter interacts strongly with the nanotube, which prevents the GaNNT from being reused.

scholarly journals The stability and electronic and photocatalytic properties of the ZnWO4 (010) surface determined from first-principles and thermodynamic calculations

RSC Advances ◽  
2021 ◽  
Vol 11 (38) ◽  
pp. 23477-23490
Author(s):  
Yonggang Wu ◽  
Jihua Zhang ◽  
Bingwei Long ◽  
Hong Zhang
Keyword(s):  
Phase Diagram ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Thermodynamic Calculations ◽  
Photocatalytic Properties ◽  
Thermodynamic Approach ◽  
Functional Theory ◽  
Stability Phase Diagram ◽  
The Stability

The ZnWO4 (010) surface termination stability is studied using a density functional theory-based thermodynamic approach. The stability phase diagram shows that O-Zn, DL-W, and DL-Zn terminations of ZnWO4 (010) can be stabilized.

STRUCTURES, ABSORPTION SPECTRA, AND ELECTRONIC PROPERTIES OF POLYFLUORENE AND ITS DERIVATIVES: A THEORETICAL STUDY

2006 ◽  
Vol 05 (03) ◽  
pp. 595-608 ◽  
Author(s):  
KRIENGSAK SRIWICHITKAMOL ◽  
SONGWUT SURAMITR ◽  
POTJAMAN POOLMEE ◽  
SUPA HANNONGBUA
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Level Energy ◽  
Excitation Energies ◽  
Lumo Energy ◽  
Functional Theory ◽  
Local Energy Minimum ◽  
Pi Systems ◽  
Homo Lumo

The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexylfluorene (DHPF), 9,9-dioctylfluorene (PFO), and bis(2-ethylhexyl)fluorene (BEHPF) — were calculated at the B3LYP/6-31G* level. Energy gaps and effective conjugation lengths of the corresponding polymers were obtained by extrapolating HOMO-LUMO energy differences and the lowest excitation energies to infinite chain length. The lowest excitation energies and the maximum absorption wavelength of polyfluorene were also performed, employing the time-dependent density functional theory (TDDFT) and ZINDO methods. The extrapolations, based on TDDFT and ZINDO calculations, agree well with experimental results. These theoretical methods can be useful for the design of new polymeric structures with a reducing energy gap.

Sign in / Sign up

Export Citation Format

Share Document