Investigation Ability of Two-Dimensional Nano Materials for Detection Toxic Gases

In this study, pure graphene nano-ribbon were used to detect toxic gases under study, which are carbon monoxide, hydro cyanide and methane. The study focused on describing graphene nano-ribbons as sensors for these gases and their use in environmental applications. Quantitative computing methods have been used to calculate the properties of the ground state by density function theory (DFT) and the properties of the stationary state, it was computed by using the time-dependent Schrödinger equation. Ground-state calculations include geometric optimization, total energy, ionization potential, electron affinity, molecular orbit energies, energy gap, adsorption energy and infrared spectrum. Whereas, the time-dependent Schrödinger equation calculations included the UV-Visible spectrum calculations, in order to characterize them as detectors of toxic gases. It was found by studying the adsorption of pure graphene nano-ribbons is sensitive to carbon monoxide, clearly and higher than hydro cyanide and methane. Also, as a result of the chemical reaction, there is a clear effect on the values of the energy gap, the ionization potential, and other associated properties. The effect of the chemical reaction continues at an adsorption distance of 2 angstroms from the surface. As for the infrared radiation calculations, it showed that the appearance of free radicals of adsorbed gases on the surface of the nano-ribbons is a clear evidence of the occurrence of chemical reaction with high energy. Through the results, the calculations of the UV-visible spectrum showed a clear shift in the computed spectrum at the ranges of high-energy interaction (34.0385-22.3212) and (15.7433-3.3246) electron volts for both nano-ribbons.

Download Full-text

Erratum: Ground state structure of high-energy-density polymeric carbon monoxide [Phys. Rev. B 95 , 144102 (2017)]

Physical Review B ◽

10.1103/physrevb.97.019902 ◽

2018 ◽

Vol 97 (1) ◽

Author(s):

Kang Xia ◽

Jian Sun ◽

Chris J. Pickard ◽

Dennis D. Klug ◽

Richard J. Needs

Keyword(s):

Carbon Monoxide ◽

Energy Density ◽

Ground State ◽

High Energy ◽

High Energy Density ◽

Ground State Structure ◽

State Structure ◽

Polymeric Carbon

Download Full-text

Ground state structure of high-energy-density polymeric carbon monoxide

Physical Review B ◽

10.1103/physrevb.95.144102 ◽

2017 ◽

Vol 95 (14) ◽

Cited By ~ 9

Author(s):

Kang Xia ◽

Jian Sun ◽

Chris J. Pickard ◽

Dennis D. Klug ◽

Richard J. Needs

Keyword(s):

Carbon Monoxide ◽

Energy Density ◽

Ground State ◽

High Energy ◽

High Energy Density ◽

Ground State Structure ◽

State Structure ◽

Polymeric Carbon

Download Full-text

X-Ray Studies on PbS

Materials Science Forum ◽

10.4028/www.scientific.net/msf.699.153 ◽

2011 ◽

Vol 699 ◽

pp. 153-165

Author(s):

M. Ambika ◽

R. Saravanan

Keyword(s):

Energy Gap ◽

Visible Spectrum ◽

Particle Size Analysis ◽

Sem Analysis ◽

Entropy Method ◽

Size Analysis ◽

Lead Sulphide ◽

X Ray ◽

Refinement Method ◽

Uv Visible

In this work, lead sulphide has been characterized using X- ray diffraction, SEM, EDX and UV-Visible techniques. X-ray analysis is done by using the Rietveld refinement method of matching the observed and calculated profiles, and then the results obtained from the refinement process are used in finding the electron density distribution by using maximum entropy method (MEM). The local structure analysis of PbS is done by the pair distribution function (PDF). Particle size analysis is done with the use of XRD data, SEM analysis is done in finding the surface structure and EDX in finding the elemental composition of PbS sample. The energy gap of PbS is found from UV-Visible spectrum.

Download Full-text

Band Gap Energy for SiC Thin Films Prepared By TEACO2 Laser Irradiated With Nuclear Radiation

Baghdad Science Journal ◽

10.21123/bsj.6.3.578-583 ◽

2009 ◽

Vol 6 (3) ◽

pp. 578-583

Author(s):

Baghdad Science Journal

Keyword(s):

Thin Films ◽

Energy Gap ◽

Energy Levels ◽

High Energy ◽

Band Gap Energy ◽

Nuclear Radiation ◽

Gamma Source ◽

High Energy Radiation ◽

Energy Gaps ◽

Uv Visible

The effect of high energy radiation on the energy gap of compound semiconductor Silicon Carbide (SiC) are viewed. Emphasis is placed on those effects which can be interpreted in terms of energy levels. The goal is to develop semiconductors operating at high temperature with low energy gaps by induced permanent damage in SiC irradiated by gamma source. TEACO2 laser used for producing SiC thin films. Spectrophotometer lambda - UV, Visible instrument is used to determine energy gap (Eg). Co-60, Cs-137, and Sr-90 are used to irradiate SiC samples for different time of irradiation. Possible interpretation of the changing in Eg values as the time of irradiation change is discussed

Download Full-text

DFT Study of Chemical Adsorption of NO2 Gas on Graphene Nano Material

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1039.391 ◽

2021 ◽

Vol 1039 ◽

pp. 391-397

Author(s):

Mohammed A. Al-Seady ◽

Nihal A. Abdul Wahhab ◽

Hamid I. Abbood ◽

Hayder M. Abduljlil

Keyword(s):

Adsorption Energy ◽

Energy Gap ◽

Theoretical Calculations ◽

Visible Spectrum ◽

High Reactivity ◽

Orbital Energy ◽

Chemical Adsorption ◽

Gas Molecule ◽

High Interaction ◽

Uv Visible

In the current study, the density function theory (DFT) is used to investigate the chemical adsorption strength of NO2 gas molecule. The relaxation structure, molecular orbital energy, energy gap and adsorption energy are calculated at ground state. The time dependent DFT (TD-DFT) used to simulate excitation provides UV-Visible spectrum. There was a perpendicular geometrical orientation of the gas molecule around the surface and an adsorption distance of 2.58 Å. The adsorption distance shows the chemical reaction between the gas molecule and the surface. The result of adsorption energy indicates that the gas molecule that closed to the surface has high interaction and it decreases gradually when gas molecule goes further from the graphene nano-ribbon surface. The UV-Visible measurement indicates that the system interaction with gas molecule has red shifting in electromagnetic radiation. The final result concludes that graphene nano-ribbon has high reactivity for NO2 gas molecule. The theoretical calculations provide the ability to design optical sensor which has useful applications in an environmental monitoring.

Download Full-text

Time Decay of Correlations in a Spin-1/2 Linear Chain

Modern Physics Letters B ◽

10.1142/s0217984998000044 ◽

1998 ◽

Vol 12 (01) ◽

pp. 17-21

Author(s):

Oscar Bolina ◽

J. Rodrigo Parreira

Keyword(s):

Magnetic Field ◽

Asymptotic Behavior ◽

Ground State ◽

Energy Gap ◽

Linear Chain ◽

Transverse Magnetic ◽

Time Dependent ◽

Time Decay ◽

Dependent Correlation ◽

Infinite Linear

We determine the asymptotic behavior of time-dependent correlation functions in a spin-[Formula: see text] infinite linear chain with a strong transverse magnetic field in terms of the energy gap of the ground state against the excited ones.

Download Full-text

Liquid-liquid extraction of succinate using a dicopper cryptate

10.26434/chemrxiv.11786784 ◽

2020 ◽

Author(s):

Riccardo Mobili ◽

Sonia La Cognata ◽

Francesca Merlo ◽

Andrea Speltini ◽

Massimo Boiocchi ◽

...

Keyword(s):

Aqueous Phase ◽

Visible Spectrum ◽

Tca Cycle ◽

Residual Concentration ◽

Waste Products ◽

Liquid Liquid Extraction ◽

The Tca Cycle ◽

Quantitative Extraction ◽

Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

Download Full-text

Investigation of Adsorption Effect of Carbon Monoxide on Coniine: A DFT Study

Letters in Organic Chemistry ◽

10.2174/1570178617666210108114822 ◽

2021 ◽

Vol 17 ◽

Author(s):

Siyamak Shahab ◽

Masoome Sheikhi ◽

Mehrnoosh Khaleghian ◽

Marina Murashko ◽

Mahin Ahmadianarog ◽

...

Keyword(s):

Carbon Monoxide ◽

Gas Phase ◽

Density Functional ◽

Energy Gap ◽

Adsorption Effect ◽

Chemical Shift Tensors ◽

Solvent Water ◽

Donor And Acceptor ◽

Before And After ◽

Electron Donor And Acceptor

: For the first time in the present study, the non-bonded interaction of the Coniine (C8H17N) with carbon monoxide (CO) was investigated by density functional theory (DFT/M062X/6-311+G*) in the gas phase and solvent water. The adsorption of the CO over C8H17N was affected on the electronic properties such as EHOMO, ELUMO, the energy gap between LUMO and HOMO, global hardness. Furthermore, chemical shift tensors and natural charge of the C8H17N and complex C8H17N/CO were determined and discussed. According to the natural bond orbital (NBO) results, the molecule C8H17N and CO play as both electron donor and acceptor at the complex C8H17N/CO in the gas phase and solvent water. On the other hand, the charge transfer is occurred between the bonding, antibonding or nonbonding orbitals in two molecules C8H17N and CO. We have also investigated the charge distribution for the complex C8H17N/CO by molecular electrostatic potential (MEP) calculations using the M062X/6-311+G* level of theory. The electronic spectra of the C8H17N and complex C8H17N/CO were calculated by time dependent DFT (TD-DFT) for investigation of the maximum wavelength value of the C8H17N before and after the non-bonded interaction with the CO in the gas phase and solvent water. Therefore, C8H17N can be used as strong absorbers for air purification and reduce environmental pollution.

Download Full-text