Raman Spectra of SF6 Decomposed Characteristic Products Based on Density Functional Theory

2021 ◽  
Vol 16 (2) ◽  
pp. 201-207
Author(s):  
Zhen-Yu Zhang ◽  
Xue-Dong Zhang ◽  
Wen-Hua Fu ◽  
Han-Bing Yan ◽  
Feng-Chun Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Raman Spectrum ◽  
Density Functional ◽  
High Efficiency ◽  
Normal Operation ◽  
Quantitative Detection ◽  
Product Analysis ◽  
Functional Theory ◽  
Decomposition Products ◽  
B3lyp Functional

SF6 decomposition product analysis is one of the most convenient and efficient methods to diagnose the potential faults of SF6 insulated electric equipment in the early stage. Based on SF6 decomposition characteristic gas analysis, the operation state of SF6 insulated power equipment can be judged by on-line monitoring, so as to ensure its normal operation. Raman spectrum analysis technology can realize the nondestructive detection of gas samples with a single wavelength laser. It has excellent applicability and high efficiency for the detection of SF6 decomposition characteristic components. In this paper, molecular configurations of CF4, CO, H2S, SO2 were obtained by B3LYP functional that based on density functional theory (DFT), and the Raman frequency and intensity characteristics were calculated by 6-31G (2df, p) basis group. The results were compared with National Institute of Standards and Technology (NIST) standard frequencies and it was found that the optimized configuration has no virtual frequency. The characteristic peaks of CO, CF4, SO2 and H2S that were identified by Raman spectrum are respectively 2221.11, 908.97, 1175.24 and 2688.82 cm-1, which are basically consistent with the corresponding NIST standard values. This study not only shows that the Raman spectrum of SF6 decomposition products calculated by B3LYP functional function is reliable, but provides a reference for the quantitative detection of SF6 decomposition products based on Raman spectrum.

scholarly journals OPTIMASI SIFAT INHIBITOR KOROSI SENYAWA THIAAMIDA-PIRAZOLINDOL BERDASARKAN TEORI FUNGSIONAL KERAPATAN

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Saprini Hamdiani ◽  
Jannatin Arduha ◽  
Agus Abhi Purwoko ◽  
Saprizal Hadisaputra
Keyword(s):  
Density Functional Theory ◽  
Corrosion Inhibitor ◽  
Density Functional ◽  
Significant Contribution ◽  
High Efficiency ◽  
Chemical Parameters ◽  
Functional Theory ◽  
Quantum Chemical Parameters ◽  
Corrosion Inhibition Efficiency ◽  
Electron Donating Groups

Abstrak. Sifat inhibitor korosi senyawa turunan thiaamida-pirazolindol (TP) telah dikaji menggunakan teori fungsional kerapatan pada tingkatan teori B3LYP/6-31G(d). Pengaruh gugus substitusi pendonor dan penarik elektron (NH2, SH, CHCH2, CH3, OH, CHO, COOH, F, NO2) terhadap efisiensi anti korosi senyawa thiaamida-pirazolindol juga dihitung. Parameter kuantum untuk senyawa anti korosi seperti energi orbital (EHOMO dan ELUMO), potensial ionisasi (I), afinitas elektron (A) dan elektronegativitas (χ) memiliki hubungan yang linier dengan efisiensi anti korosi (IE%) senyawa turunan thiaamida-pirazolindol. Gugus pendonor elektron meningkatkan nilai IE%. Urutan kenaikan IE% adalah NO2 < CHO < COOH < F < CHCH2 < OH < CH3 < NH2. Penambahan gugus pendonor elektron amina (NH2) meningkatkan IE% hingga 98,76 % dibandingkan IE% thiaamida-pirazolindol murni 90,80 %. Penambahan gugus penarik elektron menurunkan IE% hingga mencapai 82,82 %. Kajian teoritis ini akan berkontribusi besar dalam mendesain dan sintesis senyawa inhibitor organik dengan efisiensi inhibitor tinggi.Kata kunci: inhibitor korosi, teori fungsional kerapatan, thiaamida-pirazolindolAbstract. Corrosion inhibitor properties of thiamide pyrazolindole and its derivatives has been elucidated by means of density functional theory (DFT) at B3LYP/6-31G(d) level of theory. Effect of electron donating and withdrawing groups such as NH2, SH, CHCH2, CH3, OH, CHO, COOH, F and NO2 on the corrosion inhibitor of thiamide pyrazolindole derivatives also have been studied. The quantum chemical parameters such as the frontier orbital energies (EHOMO), ionization potential (I), electron affinity (A) and electronegativity (χ) are closely related to the corrosion inhibition efficiency (IE%) of thiamide pyrazolindole derivatives. The presence of electron donating groups increases IE% values meanwhile electron withdrawing groups reduce IE% values. The enhancement of IE% follows NO2 < CHO < COOH < SH < F < CH3 < CHCH2 < OH < NH2. Electron donating NH2 group gives 98,76 % of IE%, pure thiamide pyrazolindol IE% = 90,80 %. In contrast, electron withdrawing NO2 group gives IE% only 82,82 %. This theoretical study would have a significant contribution in designing high-efficiency organic corrosion inhibitors.Keywords: corrosion inhibitors, density functional theory, thiamide pyrazolindol

scholarly journals The Carbonate-catalyzed Transesterification of Sunflower Oil for Biodiesel Production: in situ Monitoring and Density Functional Theory Calculations

2021 ◽  
Vol 74 ◽  
Author(s):  
M. Nyepetsi ◽  
F. Mbaiwa ◽  
O.A. Oyetunji ◽  
N.Y. Dzade ◽  
N.H. de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Sunflower Oil ◽  
Density Functional ◽  
Ph Monitoring ◽  
Transesterification Reaction ◽  
Biodiesel Production ◽  
In Situ Monitoring ◽  
Product Analysis ◽  
Functional Theory ◽  
Promising Alternative

ABSTRACT Biodiesel has emerged as a promising alternative fuel to replace dwindling fossil-based resources, particularly in view of its added environmental merit of reducing additional air pollution. Its specific attraction stems from the similarity of its physical properties to fossil fuel-derived diesel. Although the production of biodiesel is a relatively straightforward process, reaction progress monitoring and product analysis require costly specialist equipment, such as gas chromatography and mass spectrome-try. In this study, we investigate the use of pH in monitoring the progress of carbonate-catalyzed transesterification reactions. Specifically, we focus on potassium and sodium carbonates and sunflower oil. Our results are consistent with the results obtained by other studies using different methods of monitoring. To test the generality of the method, pH measurements were also used to monitor the progress of the potassium carbonate transesterification reaction in the presence of added water, glycerol and gamma-valerolactone (GVL). The obtained results are as expected, with a limited amount of water increasing the trans-esterification rate; glycerol slowing the reaction slightly in accord with Le Chatellier's principles; and GVL increasing the rate due to co-solvent effects. Atomic-level insights into the adsorption mechanism of methanol and water on the (001) surfaces of Na2CO3 and K2CO3 catalysts are provided by first-principles DFT calculations, which explain the increase in transesterification reaction rate upon the addition of water. Keywords: Transesterification, pH monitoring, biodiesel , Density Functional Theory ( DFT), co-solvent.

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.

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