Electron Density Of Compounds Research Articles

Investigation of the Mass Attenuation Coefficients, Effective Atomic Numbers and Electron Densities for Compounds of Painkiller

In this study the effects of gamma radiations with compounds are an important subject in the field of medicine, radiation shielding and radiation physics. With technological advances the using of radiation has increased in the medicine in the last century. The mass absorpsion coefficient (µ/ρ) is the fundamental a quantity characterizing gamma ray and is of major importance in radiation shielding. In this study, the mass absorption coefficient of painkillers named Ketoprofen, Flurbiprofen, Etodolac, Ibuprofen, Meloxicam, Diclofenac and Aspirin were calculated at energy range from 4.65 keV to 59.543 keV using the WinXCom data programme. In addition total atomic (σta), moleculer (σtm), electronic cross-section (σte), effective atomic number (Zeff), effective electron density (Neff) were calculated.

Mô phỏng hệ đo Rayleigh-Compton bằng phương pháp Monte Carlo

In this study, the Monte Carlo method is applied for simulating the Rayleigh-Compton measurement system using the Si(Li) detector on MCNP6 software. In which, incident photon’s energy is 59.54 keV of 241Am source and the scattering angle is determined at 124o. The targets are elements in the range of atomic numbers from 13 to 82. Besides the simulation, the theoretical values of Rayleigh-Compton ratio were calculated basing on NRFF, RFF, MFF models on MATLAB software. The results of the Rayleigh-Compton ratio from the simulation and the theoretical calculation have an average discrepancy of 4%. In conclusion, by utilizing the Rayleigh-Compton measurement system model, the effective atomic number and electron density of compounds can be determined more accurately, conveniently, and quickly.

Characterization of electronic features of intermolecular interactions involving organic fluorine: Inputs from in situ cryo-crystallization studies on [sbnd]F and [sbnd]CF3 substituted anilines

Experimental in situ cryo-crystallization studies performed on aniline derivatives depicts that the molecular packing of these compounds is through the utilization of Csp3/sp2F⋯FCsp3/sp2, NH⋯FCsp3/sp2, and CH⋯FCsp3/sp2 interactions in the presence of strong NH⋯N hydrogen bonds. This exercise has resulted in the identification of frequently occurring supramolecular synthons involving highly electronegative, less polarizable fluorine atoms in the packing of molecules of F and CF3 substituted anilines which are liquids at ambient temperature and pressure in the solid state. These studies demonstrate the nature, energetics and topological properties derived from the electron density in compounds based on F and CF3 substituted anilines (8 anilines) in the solid state. The energetics obtained from PIXELC associated with inclusive intermolecular interactions with significantly high electrostatic contribution is mentionable. The topological analysis brings out the bonding character of these interactions in the crystal packing. It is indeed noteworthy that in situ cryo-crystallization in 2-fluoro-6-(trifluoromethyl)aniline forms unique C(sp2)Fδ+⋯Fδ−C(sp2) contacts stabilized via electrostatics between the two molecules in the asymmetric unit in addition to NH⋯N H-bonds. This feature is also observed in a related isomeric compound, namely 2-fluoro-3-(trifluoromethyl)aniline and establishes the importance of weak fluorine-centered halogen interactions in nucleation and crystal growth.

Effective atomic numbers and electron densities for some lanthanide oxide compounds using direct method in the energy region of 1 keV - 20 MeV

In this paper, the effective atomic numbers and electron densities representing interaction of gamma rays with oxides of lanthanides have been studied. The effective atomic numbers for photon energy-absorption ( Z PEAeff ) and photon interaction ( Z PIeff ), and relative to air Z Reff , the effective electron densities for photon energy-absorption ( N PEAeff ) and photon interaction ( N PIeff ) were calculated using the values of the mass attenuation and energy absorption coefficients. The variation of Z PEAeff , Z PIeff , Z Reff , N PEAeff and N PIeff with energy were shown graphically. In the continuous energy region, it was observed that there are agreements and disagreements between photon interaction and photon energy-absorption for effective atomic numbers and electron densities of compounds in different energy regions. In addition, absorption edge effects on effective atomic numbers leading more than a single value of effective atomic number at a specific energy have been discussed for the given compounds. Comparisons with experiments wherever possible have been carried out for calculated values of Z eff and N eff .

B=N Bonds and BCN Rings – Reactivity and Charge Density Studies

Abstract (F5C6)2BNMe2 (1) was prepared and (F3C)2BNMe2 (2) was resynthesized. The crystal structures of both compounds were determined. In contrast to 2, compound 1 does not react with diazomethanes under carbine insertion into the BN bond. In this way the known (F3C)2BCH(SiMe3)NMe2 (3) was resynthesized from 2 and its solid‐state structure was determined. The electron densities of compounds 1, 2, and 3 and those of the simpler model compound (F3C)2BCH2NMe2 (4) as well as that of the BN/CC isoelectronic compound (F3C)2CCH2CMe2 (5) for comparison were calculated and their topologies analysed in terms of the Quantum Theory of Atoms in Molecules (QTAIM). Despite 2 has a shorter B–N bond in calculations and in the crystal than 1, the atomic charges and electron density parameters to QTAIM are very similar for both compounds and cannot explain the different reactivity. The three‐membered rings 3 and 4 do not show bond‐critical points for their B–N bonds. The nature of the B–N bond region was also analysed in terms of the source function contributions in QTAIM, which demonstrated the importance of the close proximity of a third atom in three‐membered rings for the charge density topologies in such systems.

Photon mass attenuation coefficients, effective atomic numbers and electron densities of some thermoluminescent dosimetric compounds

Photon mass attenuation coefficients of some thermoluminescent dosimetric (TLD) compounds, such as LiF, CaCO3, CaSO4, CaSO4.2H2O, SrSO4, CdSO4, BaSO4, C4H6BaO4 and 3CdSO4.8H2O were determined at 279.2, 320.07, 514.0, 661.6, 1115.5, 1173.2 and 1332.5 keV in a well-collimated narrow beam good geometry set-up using a high resolution, hyper pure germanium detector. The attenuation coefficient data were then used to compute the effective atomic number and the electron density of TLD compounds. The interpolation of total attenuation cross-sections of photons of energyE in elements of atomic numberZ was performed using the logarithmic regression analysis of the data measured by the authors and reported earlier. The best-fit coefficients so obtained in the photon energy range of 279.2 to 320.07 keV, 514.0 to 661.6 keV and 1115.5 to 1332.5 keV by a piece-wise interpolation method were then used to find the effective atomic number and electron density of the compounds. These values are found to be in agreement with other available published values.