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1 - Numerical investigation of the fullerene and doped fullerene effects on thermal performance of water base-fluid
Ahmad Saadi Hamid Reza Vanaie Mojtaba Yaghobi Ebrahim Heidari Darush MastiIn this study, the fullerenes have been inserted into water base-fluid to investigate the atomic and thermal behavior of nanofluid and hybridnanofluid as heat transfer fluid. This choice derives from low cast and high thermal stability of this nanostructure. Our computa چکیده کاملIn this study, the fullerenes have been inserted into water base-fluid to investigate the atomic and thermal behavior of nanofluid and hybridnanofluid as heat transfer fluid. This choice derives from low cast and high thermal stability of this nanostructure. Our computational results from Molecular Dynamics (MD) simulations indicate that the addition of nanoparticles with 4% atomic ratio produced an appreciable effect on the nanofluid. The maximum value of density, velocity, and temperature profile have reached to 0.029 atom/cubic angstrom, 0.005 angstrom/ps, and 321 centigrade degree. Its thermal conductivity would increase to 0.82 W/m.K. Heat flux reached to 2019 kW/m2 after t= 10 ns. Also, the aggregation phenomenon detected after t= 5.84 ns. This hybridnanofluid has been used to enhance the energy efficiency of the heat exchangers at high temperature for the nuclear industry applications for the first time. Numerically, by the temperature increase of nanofluid structure to 625.15 K, thermal power of nanofluid reached to 3881 MW. The thermal performance of hybridnanofluid can be improved by more than 30% by adding concentration of fullerene and doped fullerene at 4 vol%. پرونده مقاله -
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2 - Phonon-induced superconductivity and physical properties in intercalated fullerides Rb3C60
Dinesh Varshney Rajendra Jain Namita SinghAbstractThe nature of electron pairing mechanism and physical properties leading to superconducting state and normal state resistivity in alkali metal (Rb) intercalated fullerenes are explored. Keeping in mind that free electrons in lowest molecular orbital are coupled چکیده کاملAbstractThe nature of electron pairing mechanism and physical properties leading to superconducting state and normal state resistivity in alkali metal (Rb) intercalated fullerenes are explored. Keeping in mind that free electrons in lowest molecular orbital are coupled with inter-molecular phonons, the coupling with inter-molecular phonon leads to transition temperature (Tc) of about 4.17 K. The electrons also couple with the intra-molecular phonons. Within the framework of strong coupling theory, Tc is estimated at 34 K. The carbon isotope effect exponent, the energy gap ratio, influence of pressure and volume on Tc, and thermodynamical parameters describing the superconducting state confer that Rb3C60 as s-wave superconductor. Estimated contribution to resistivity using scattering with inter- and intra-molecular phonon, when subtracted from single crystal data, infers quadratic temperature dependence over most of the temperature range and is attributed to electron–electron inelastic scattering. Both low frequency intermolecular and high frequency intra-molecular phonons have significant bearing in Rb3C60 superconductor. پرونده مقاله -
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3 - The Possibility of Selective Adsorption and Sensing of the Noble Gaseous Species by the C20 Fullerene, the Graphene Sheets, and the N4B4 Cluster
Parvaneh PakravanThere are only a handful reports about the sensor systems having the ability of detecting the existence of the noble gases. Chemical reluctance of these gaseous species causes them to have no chemical interactions like hydrogen bonding with the chemically designed nano- چکیده کاملThere are only a handful reports about the sensor systems having the ability of detecting the existence of the noble gases. Chemical reluctance of these gaseous species causes them to have no chemical interactions like hydrogen bonding with the chemically designed nano-sized sensors. Noble gasses usually have no atomic charges nor do change the total polarity of the molecular sensor systems. These conditions might be more strongly observed for the cases of the lighter noble gases like helium. These properties impede designing molecular sensors for detecting the existence of the noble gasses. Due to these, in this project, we have tried to examine the ability of N4B4 cluster, C20 fullerene, and the graphene segment as especial nano-sized systems in adsorbing and detecting the existence of some noble gasses, by changing their electrical conductivity. The results showed that the N4B4 cluster could sense the existence of the noble gases, better and more selective than the C20 fullerene, or the graphene segment. پرونده مقاله -
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4 - Investigating the Effect of Fullerene (C20) Substitution on the Structural and Energetic Properties of Tetryl by Density Functional Theory
Mohammad Jalali Sarvestani Roya AhmadiThe substitution reaction of pure, silicon doped and germanium doped fullerenes and tetryl were evaluated computationally at two configurations, in this study. For this purpose, all of the studied structures were optimized geometrically and then IR and NBO calculations چکیده کاملThe substitution reaction of pure, silicon doped and germanium doped fullerenes and tetryl were evaluated computationally at two configurations, in this study. For this purpose, all of the studied structures were optimized geometrically and then IR and NBO calculations were performed on them in the temperature range of 300-400 K at 10˚ intervals. The obtained negative values of Gibbs free energy variations(ΔGf), formation enthalpy alterations (ΔHf) and great values of thermodynamic equilibrium constant (Kth) prove that the reaction of the doped and also undoped fullerenes with tetryl is exothermic, spontaneous, one-sided and experimentally feasible. The impact of temperature on the thermodynamic parameters of the reaction was also inspected and the results indicate that 298.15 K is the optimum temperature for the synthesis of all of the derived products from the interaction of tetryl and the studied nanostructures. The calculated specific heat capacity values (Cv) show that the sensitivity of tetryl to the shock and heat has decreased significantly after its junction to fullerene nanostructures. Moreover, the increasing of N-O bond lengths after the fullerene substitution shows that the explosive power of tetryl has defused after its binding to the surface of fullerene. The obtained density values demonstrate that germanium doped C20 has the best impression on the improvement of the blasting power of tetryl in comparison to ordinary and silicon doped fullerene. پرونده مقاله -
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5 - Theoretical investigation about the adsorption of the Sarin nerve agent on C20 fullerene and its boron-doped derivative
Morteza RouhaniSarin is a very toxic organophosphorus chemical warfare agent which has been used in different wars. According to an immediate demand of detection, secure approachs to break down this toxic nerve agent, the study on decomposition of sarin achieve significance. In this w چکیده کاملSarin is a very toxic organophosphorus chemical warfare agent which has been used in different wars. According to an immediate demand of detection, secure approachs to break down this toxic nerve agent, the study on decomposition of sarin achieve significance. In this work, we have made endeavors of discovering an approach to neutralize this hazardous kind by adsorption of this molecule by C20 fullerene and its boron doped derivative. The results show that Sarin can form interactions with the C20 cage in its neutral state and the interactions can be enhanced significantly by introducing an extra boron atom to the system. The adsorption energy values and equilibrium distances for various adsorption states were calculated, and it was found that the GB molecule adsorbs onto the boron doped derivative with greater affinity than on pure fullerene. Probably, the GB is physisorbed on fullerene, while its adsorption on the boron doped derivative from O and P heads has a chemical nature. In that case, a partial positive charge was developed on boron atom, and was delocalized by O-P=O functional group in GB. As a result, GB is chemisorbed on boron doped derivative, contrary to the GBfullerene interaction, which occurs physically. پرونده مقاله -
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6 - Fullerene (C24) as a Nanocarrier for Procarbazine Anticancer Drug: A Density Functional Theory Investigation
Mohammad Jalali Sarvestani Roya AhmadiProcarbazine is an anticancer medicine with serious side effects in this respect the capability of fullerene C24 as a nanocarrier for this drug was scrutinized computationally. For this purpose, all of the studied structures were optimized geometrically, then IR and FMO چکیده کاملProcarbazine is an anticancer medicine with serious side effects in this respect the capability of fullerene C24 as a nanocarrier for this drug was scrutinized computationally. For this purpose, all of the studied structures were optimized geometrically, then IR and FMO calculations were performed on them in the temperature range of 278.15-308.15 K at 3˚ intervals. The obtained negative values of Gibbs free energy variations(ΔGad), adsorption enthalpy alterations (ΔHad), and great values of the thermodynamic equilibrium constant (Kth) prove that the interaction of the fullerene with procarbazine is exothermic, spontaneous, one-side, and experimentally feasible. The impact of temperature on the thermodynamic parameters of the reaction was also inspected and the results indicate that 278.15 K is the optimum temperature for the synthesis of all of the derived products from the interaction of procarbazine and the studied nanostructure. Some important structural parameters such as band gap, chemical hardness, chemical potential, electrophilicity, and maximum transferred charge capacity were also discussed in detail. پرونده مقاله -
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7 - Investigating the Effect of Fullerene (C20) Substitution on the Structural and Energetic Properties of 3-picrylamino-1, 2, 4-triazole by Density Functional Theory
Mohammad Jalali Sarvestani Roya AhmadiThe substitution reaction of fullerene with 3-picrylamino-1,2,4-triazole (PATO) were evaluated computationally at two configurations, in this study. For this purpose, all of the studied structures were optimized geometrically, then IR and NBO calculations were performed چکیده کاملThe substitution reaction of fullerene with 3-picrylamino-1,2,4-triazole (PATO) were evaluated computationally at two configurations, in this study. For this purpose, all of the studied structures were optimized geometrically, then IR and NBO calculations were performed on them in the temperature range of 298.15-398.15 K at 10˚ intervals. The obtained negative values of Gibbs free energy variations(ΔGf), formation enthalpy alterations (ΔHf) and great values of the thermodynamic equilibrium constant (Kth) prove that the reaction of the fullerene with PATO is exothermic, spontaneous, one-sided and experimentally feasible. The impact of temperature on the thermodynamic parameters of the reaction was also inspected and the results indicate that 298.15 K is the optimum temperature for the synthesis of all of the derived products from the interaction of PATO and the studied nanostructures. The calculated specific heat capacity values (Cv) show that the sensitivity of PATO to the shock and heat has decreased significantly after its junction to fullerene nanostructures. The obtained density values demonstrate that C20 has an excellent impression on the improvement of the blasting power of PATO. پرونده مقاله -
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8 - Cyeloaddition Reactions Between C30 and Huta- 1,3 -diene An ab initio Study
Seeid Abedini Khorrami Shahram Moradi Hajar Mohammadzadeh BaharCycloaddition reaction between C30 and hula-I, 3-diene was studied within the Snimework of AM I (RHF)level. The reaction involving the double bond between two hexagons and a hexagon and a pentagon, as wellas the cycloaddition products followed by disrotatory ogs s elect چکیده کاملCycloaddition reaction between C30 and hula-I, 3-diene was studied within the Snimework of AM I (RHF)level. The reaction involving the double bond between two hexagons and a hexagon and a pentagon, as wellas the cycloaddition products followed by disrotatory ogs s electrocyclic ring openings were considered.Thermodynamics parameters and stability energy and innsation state are evaluated in three Valence isomers پرونده مقاله -
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9 - Theoretical Structural and Spectral Analyses of TEMPO Radical Derivatives of Fullerene
Fatih Ucun Serkan Kaya Halil OturakThe spectroscopic properties of the 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) radicalderivatives of the fullerene (C60) were theoretically investigated. The ground state optimizedstructures of the radical adducts of the fullerene were calculated by using DFT (B3LYP) چکیده کاملThe spectroscopic properties of the 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) radicalderivatives of the fullerene (C60) were theoretically investigated. The ground state optimizedstructures of the radical adducts of the fullerene were calculated by using DFT (B3LYP) with 6-31G(d) level. It was concluded that a 6-6 ring junction of C60 moiety generally covalently links to thepiperidine ring of the TEMPO derivatives, directly. The optimization characteristics of all thefullerene radical derivatives indicate generally a annulene structure while C60+TEMPO indicate acyclopropane structure which is formed by the link of the carbon of the piperidine ring doubly to a 6-6 ring junction of C60. The calculated isotropic hyperfine coupling constants, vibrational frequenciesand UV- Vis transition energies of all the radical adducts were seen to be in good agreement with thecorresponding experimental data. The UV-Vis transitions and their energies were determined withcorresponding to the experimental values. In the IR analysis the shifts of vibrational frequencies havebeen commented by comparison with those belonged to the pure C60. Also the some selectedgeometrical parameters with together the cage width and the cage length for the ground stateoptimized structures of all the radical adducts were listed, and the binding energies of the radicalswere obtained. پرونده مقاله -
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10 - Theoretical and Structural Relationship Study of Electrochemical Properties of p- Sulfonated Calix[Slarene Macrocycles with Fullerenes as lp-Sulfonated Calliplarenesi@iCsl Supramolecular Complexes
Avat (Armen) Taherpour Karim Zare Leila BakhtiariUp to now, various empty carbon fullerenes with different magic number "n", such as C10, Cow Cm, Cso,Cis** Cm and so on. have been obtained. The calix[n]arenes are a class of chalice-like rnacrocyclicmolecules that have attracted widespread attention as complex molecule چکیده کاملUp to now, various empty carbon fullerenes with different magic number "n", such as C10, Cow Cm, Cso,Cis** Cm and so on. have been obtained. The calix[n]arenes are a class of chalice-like rnacrocyclicmolecules that have attracted widespread attention as complex molecules with liquid crystal behaviors.These classes of compounds are cyclic ohgomers synthessid by condensation of a para-alkylated phenoland formaldehyde. Quantitative structural relationships have been successfully used to construct effectiveand useful mathematical methods for finding good relationships between structural data and the variouschemical and physical properties. To establish a good structural relationship between the structures offidlerenes C, (n 60, 70, 76, 82 and 86) with p-sulfonated calix[8]arene as supramolecular Brysulfonatedcalix[8]azeneTDIC„) complexes was utilized the number of carbon atoms of the fullerenes "n". In thisstudy, the relationship between number of carbon atoms and the four free energies of electron transfer(40„,7) to 4Gry.0) as assessed using oxidation reduction equation between fullerenes C„ (n 4 60, 70, 76. 82and 86) 1-5 and p-sulfonated ealixI8larene (6) as [P-sulfonated calirltiIarene]@IBti surranteltenarcomplexes (A-E) are presented. The results were extended to calculate she four free energies of electrontransfer (alGtiti, to <1.G.,,4)) of other supramolecular complexes for fullerenes Ctis to Cm, and p-sulfonatedcalm [8] arenes A-I to 4-1. پرونده مقاله -
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11 - Free Energies of Electron Transfer, Electrochemical Properties, Electron Transfer Kinetic Theoretical and Quantitative Structural Relationship Studies of Cn@X-[HbA] (HbA=Hemoglobin A; X= - and -Fumarate Crosslinked Hemoglobins (XL & XL)) Nanostructure Complexes
Avat (Arman) Taherpour Leila FathiyanThe binding, release and oxidation of oxygen occur at the heme group iron ion. Hemoglobinoxidation-reduction studies have been previously performed using spectroelectrochemistry (SEC) andhave provided insight into the hemoglobin electron transfer process and more specif چکیده کاملThe binding, release and oxidation of oxygen occur at the heme group iron ion. Hemoglobinoxidation-reduction studies have been previously performed using spectroelectrochemistry (SEC) andhave provided insight into the hemoglobin electron transfer process and more specifically, into theheme group electronic factor and subunit interaction influences. In this study, the number of fullerenecarbon atoms was used as an index to establish a relationship between the structures of hemoglobin Aand - and -fumarate crosslinked hemoglobins, which were designated as HbA, XL and XL-[HbA] 1-3, respectively. These compounds represent the most well-known blood molecular systemsand fullerenes (Cn, where n = 60, 70, 76, 82 or 86), which generated the following complexes:Cn@[HbA], A-1 to A-5; Cn@DXL-[HbA], B-1 to B-5 and Cn@EXL-[HbA], C-1 to C-5. Therelationship between the carbon atom number and electron transfer free energies (Get) were assessedusing the Rehm-Weller equation for A-1 to A-5, B1 to B-5 and C-1 to C-5 supramolecular Cn@X-[HbA] (where HbA = hemoglobin A; X = - and -fumarate crosslinked hemoglobins (XL & XL))and complexes 4-57, which possessed different electrochemical properties. Calculations werepresented for the first Cn oxidation potentials (Ox.E1). The results were used to calculate the electrontransfer first free energies (Get(1)) of supramolecular complexes A-1 to A-5, B1 to B-5 and C-1 to C-5 for fullerenes C60 to C300. The first free activation energies and kinetic rate constants of the electrontransfers, G#et(n) (Get(1)#) and ket, respectively, were also calculated in this study for A-1 to A-7, B1to B-7 and C-1 to C-7 (compounds 4-24) in accordance with the Marcus theory. پرونده مقاله -
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12 - A Comparative DFT Study on Structural and Electronic Properties of C24 and Some of Its Derivatives: C12B6N6, B6N6C12 and B12N12
M. Anafche F. NaderiThe structural stabilities, geometry and electronic properties of C24 and some its heterofullerenederivatives are compared at the B3LYP/6-311-EFG**//B3LYP/6-31+G* level of theory. Vibrationalfrequency calculations show that all the systems are true minima. The calculate چکیده کاملThe structural stabilities, geometry and electronic properties of C24 and some its heterofullerenederivatives are compared at the B3LYP/6-311-EFG**//B3LYP/6-31+G* level of theory. Vibrationalfrequency calculations show that all the systems are true minima. The calculated binding energies ofheterofullerenes show C24 as the, most stable fullerenes by 9.03eV/atom. While decreasing bindingenergy in C12B6N6, B6N6C12 and B12Ni2 through increasing their HOMO-LUMO gap, theconductivity of them is increasing. High point charges are predicted to establish an overall chargetransfer on the surface of heterofullerene. 13C NMR of C24 fullerene consists of two lines. Dopedmodels show several lines at different positions relative to lines for C24 fullerene. Boron, nitrogen,and carbon adopt different roles around carbon sites. The Nucleus-independent chemical shift(NICS) calculations show more negative NICS values in BN-substituted heterofullerenes than thoseOf C24. پرونده مقاله -
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13 - Electronic Properties of Hydrogen Adsorption on the Silicon- Substituted C20 Fullerenes: A Density Functional Theory Calculations
F. R. Nikmaram Jamshid NajafpourThe B3LYP/6-31++G** density functional calculations were used to obtain minimum geometries and interaction energies between the molecular hydrogen and nanostructures of fullerenes, C20 (cage), C20 (bowl), C19Si (bowl, penta), C19Si (bowl, hexa). The H2 molecule is set a چکیده کاملThe B3LYP/6-31++G** density functional calculations were used to obtain minimum geometries and interaction energies between the molecular hydrogen and nanostructures of fullerenes, C20 (cage), C20 (bowl), C19Si (bowl, penta), C19Si (bowl, hexa). The H2 molecule is set as adsorbed in the distance of 3Å at vertical position from surface above the pentagonal and hexagonal sites of nanostructures. By comparing of gap energies, electronic chemical potential, hardness and results of QTAIM (Quantum Theory of Atom in Molecules) analysis, the Si atom substitution in hexa two- fold position of C20 (bowl)may be suitable for the adsorption of hydrogen molecule. پرونده مقاله -
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14 - مطالعه ترمودینامیکی جذب سطحی کوتیاپین بر روی سطح فولرن (C20)
محمدرضا جلالی سروستانیدر این تحقیق، محاسبات مادون قرمز (IR) و اوربیتال های پیوندی طبیعی (NBO) جهت ارزیابی عملکرد فولرن (C20) به عنوان حسگر جهت شناسایی داروی کوتیاپین مورد استفاده قرار گرفت. مقادیر منفی انرژی جذب سطحی، تغییرات آنتالپی و تغییرات انرژی آزاد گیبس نشان دادند که برهمکنش کوتیاپین و چکیده کاملدر این تحقیق، محاسبات مادون قرمز (IR) و اوربیتال های پیوندی طبیعی (NBO) جهت ارزیابی عملکرد فولرن (C20) به عنوان حسگر جهت شناسایی داروی کوتیاپین مورد استفاده قرار گرفت. مقادیر منفی انرژی جذب سطحی، تغییرات آنتالپی و تغییرات انرژی آزاد گیبس نشان دادند که برهمکنش کوتیاپین و فولرن گرما زا، خودبخودی و از لحاظ تجربی امکان پذیر است. مقادیر مثبت و بزرگ ثابت تعادل ترمودینامیکی نشان دهنده این بود که برهمکنش کوتیاپین و فولرن برگشت ناپذیر و غیر تعادلی میباشد. افزایش ظرفیت گرمایی ویژه دارو و نانو ساختار بعد از برهمکنش نشان دهنده این بود که هدایت حرارتی در حین برهمکنش افزایش چشم گیری داشته و با توجه به گرمازا بودن فرآیند میتوان از فولرن برای ساخت حسگرهای حرارتی جدید برای اندازه گیری کوتیاپین استفاده کرد. پارامترهای ساختاری مانند ، گپ انرژی، الکتروفیلیسیته، پتانسیل شیمیایی و سختی شیمیایی هم محاسبه شده و مورد بررسی قرار گرفتند. کاهش چشم گیر گپ انرژی بعد از جذب شدن دارو روی سطح نانو ساختار ثابت کرد که رسانایی الکتریکی و خاصیت الکتروکاتالیتیک بعد از برهمکنش جاذب و کوتیاپین بهبود یافته و از این نانو ساختار میتوان برای ساخت حسگر الکتروشیمیایی جدید جهت اندازه گیری کوتیاپین استفاده نمود. پرونده مقاله -
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15 - مطالعه تئوری ماهیت جذب فرمالدهید بر روی هتروفولرن C58BN با استفاده از تئوری تابعی چگالی
احسان زاهدی مجید مظفری ملیحه عربدر این تحقیق فرایند جذب فرمالدهید بر روی سطح خارجی هتروفولرن C58BN به روش تئوری تابعی چگالی در سطح نظری B3LYP/6-31G(d) مورد مطالعه قرار گرفته است. انرژیهای کل الکترونی با اضافه کردن مستقیم دو تابع تصحیحی gCP و D3 تصحیح شده اند. اتصال فرمالدهید از طریق اتم اکسیژن به بور چکیده کاملدر این تحقیق فرایند جذب فرمالدهید بر روی سطح خارجی هتروفولرن C58BN به روش تئوری تابعی چگالی در سطح نظری B3LYP/6-31G(d) مورد مطالعه قرار گرفته است. انرژیهای کل الکترونی با اضافه کردن مستقیم دو تابع تصحیحی gCP و D3 تصحیح شده اند. اتصال فرمالدهید از طریق اتم اکسیژن به بور و کربن به نیتروژن باعث انتقال جفت الکترون آزاد اتم اکسیژن به اوربیتال خالی اتم بور شده و در نهایت منجر به تشکیل یک پیوند کوالانسی قوی و پایداری سیستم میشود. در حالیکه اتصال از طریق اتم اکسیژن به نیتروژن و کربن به بور به لحاظ انرژیتیکی مساعد نیست. پارامترهای توپولوژیکی مبتنی نظریه AIM، نمودار های چگالی حالات و نقشه های پتانسیل الکتروستاتیک مولکولی نشان دادند که برهمکنش فرمالدهید با هتروفولرن C58BN در مواضع مورد مطالعه از نوع کوالانسی است. پرونده مقاله -
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16 - مطالعه داکینگ مولکولی و مکانیک کوانتومی برهمکنش کوئرستین برسطح فولرن B12N12
محمد تقی بائیجذب و فعالیت آنتی رادیکالی مولکول کوئرستین روی سطح فولرن B12N12 با کمک نظریه تابعیت چگالی(DFT) در روشهای B3PW91-D و M06-2X-D بررسی شده است. مقادیر جذب و تجزیه و تحلیل توپولوژی ها نشان داد که این مولکول به سطح فولرن B12N12 جذب شده است و تغییرات قابل توجهی در خواص الکترون چکیده کاملجذب و فعالیت آنتی رادیکالی مولکول کوئرستین روی سطح فولرن B12N12 با کمک نظریه تابعیت چگالی(DFT) در روشهای B3PW91-D و M06-2X-D بررسی شده است. مقادیر جذب و تجزیه و تحلیل توپولوژی ها نشان داد که این مولکول به سطح فولرن B12N12 جذب شده است و تغییرات قابل توجهی در خواص الکترونیکی فولرن ایجاد میکند. فعالیتهای آنتی اکسیدانی مولکول کوئرستین و کمپلکس B12N12/Que با استفاده از سطح تئوری M06-2X-D بر اساس انتقال اتم هیدروژن (HAT)، انتقال الکترون منفرد و پس از آن انتقال پروتون (SET-PT) و روش SPLET بررسی شده است. برای درک بهتر خواص آنتی اکسیدانی، مقادیر آنتالپی تفکیک پیوند (BDE)، پتانسیل یونیزاسیون (IP)، آنتالپی تفکیک پروتون (PDE)، پروتون خواهی (PA) و آنتالپی انتقال الکترون (ETE) کوئرستین روی سطح فولرن B12N12 در گاز، بنزن، اتانول و آب محاسبه شده است. نتایج نشان داد که در گاز و فازهای حلال، جذب کوئرستین روی B12N12 فولرن باعث افزایش فعالیت آنتی اکسیدانتی کوئرستین شده است،انرژی برهمکنش وثابت مهارکنندگی در روش داکینگ مولکولی نیز این نتایج را تایید میکنند. پرونده مقاله -
دسترسی آزاد مقاله
17 - بررسی جذب وخاصیت آنتی اکسیدانتی گالیک اسید روی سطح فولرن B12N12 باروش مکانیک کوانتومی DFT وداکینگ مولکولی
محمد تقی بائی خدیجه توکلی هفشجانیجذب و فعالیت آنتی اکسیدانتی گالیک اسید روی سطح فولرن B12N12 با کمک نظریه تابعیت چگالی(DFT) در روشهای B3PW91-D و M06-2X-D بررسی شده است. مقادیر انرژی جذب و خصوصیات الکترونی نشان داد که این مولکول به سطح فولرن B12N12 جذب شیمیایی شده است و تغییرات قابل توجهی در خواص الکترو چکیده کاملجذب و فعالیت آنتی اکسیدانتی گالیک اسید روی سطح فولرن B12N12 با کمک نظریه تابعیت چگالی(DFT) در روشهای B3PW91-D و M06-2X-D بررسی شده است. مقادیر انرژی جذب و خصوصیات الکترونی نشان داد که این مولکول به سطح فولرن B12N12 جذب شیمیایی شده است و تغییرات قابل توجهی در خواص الکترونیکی فولرن ایجاد گردید. فعالیتهای آنتی اکسیدانی مولکول گالیک اسید و کمپلکس B12N12/Gal با استفاده از سطح تئوری M06-2X-D بر اساس انتقال اتم هیدروژن (HAT)، انتقال الکترون منفرد و پس از آن انتقال پروتون (SET-PT) و روش SPLET بررسی شده است. برای درک بهتر خواص آنتی اکسیدانی، مقادیر آنتالپی تفکیک پیوند (BDE)، پتانسیل یونیزاسیون (IP)، آنتالپی تفکیک پروتون (PDE)، پروتون خواهی (PA) و آنتالپی انتقال الکترون (ETE) گالیک اسید روی سطح فولرن B12N12 در فاز گاز، بنزن، اتانول و آب محاسبه شده است. نتایج نشان داد که فولرن B12N12 باعث افزایش فعالیت آنتی اکسیدانتی گالیک اسید شده است. همچنین نتایج داکینگ نشان داد که انرژی واندروالس بیشترین سهم رادراین برهمکنش داشته وثابت مهارکنندگی نیز نشان دهنده افزایش قدرت فعالیت ضد رادیکالی گالیک اسید دراثر برهمکنش با فولرن بور-نیترید می باشد پرونده مقاله -
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18 - Encapsulation of Methane Molecules into C60 Fullerene Nanocage: DFT and DTFB-MD Simulations
Masoud Darvish Ganji Fahimeh Bonyasi Sepideh Tanreh Mahyar Rezvani Malak HekmatiExtensive urbanization has greatly raised the demand for cleaner coal- and petroleum-derived fuels. Mainly composed of methane, natural gas represents a promising alternative for this purpose, making its storage a significant topic. In the present research, deposition o چکیده کاملExtensive urbanization has greatly raised the demand for cleaner coal- and petroleum-derived fuels. Mainly composed of methane, natural gas represents a promising alternative for this purpose, making its storage a significant topic. In the present research, deposition of methane molecules in C60 fullerene was investigated through a combined approach wherein density functional based tight binding (DFTB) method was used to optimize the geometry while ab initio density functional theory (DFT) served as a tool for energy calculation. Doping endohedral methane molecules onto fullerene nanocage, it was witnessed that, the only stable complex might be formed by a single methane molecule entrapped inside the C60 cage. It was further indicated that, when a large number of encapsulated CH4 molecules are concerned, occasional chemisorption of the molecules on the inner surface of the cage would occur, ending up breaking the capsule side wall at NCH4=7. Further studied by density-functional tight-binding molecular dynamics (DFTB-MD) simulation, mechanism of the breakage indicated this complex as being highly unlikely to be stable. پرونده مقاله -
دسترسی آزاد مقاله
19 - The Analysis of Coulomb Blockade in Fullerene Single Electron Transistor at Room Temperature
Vahideh KhademHosseini Mohammad Taghi Ahmadi Saeid Afrang Razali IsmailThe Graphene based single electron transistor (SET) as a coulomb blockade device need to be explored .It is a unique device for high-speed operation in a nano scale regime. A single electron transfers via the coulomb barriers, but its movement may be prevented by coulom چکیده کاملThe Graphene based single electron transistor (SET) as a coulomb blockade device need to be explored .It is a unique device for high-speed operation in a nano scale regime. A single electron transfers via the coulomb barriers, but its movement may be prevented by coulomb blockade, so its effect is investigated in this research. The conditions of coulomb blockade and its controlling factors such as material, temperature, gate voltage and island length are investigated. At first, the coulomb blockade on fullerene SET as a nano transistor with new material is modeled and compared with experimental data of silicon SET. The comparison study indicates that the coulomb blockade range of fullerene SET is lower than the silicon one. On the other hand, the analysis demonstrates that, temperature and gate voltage play direct associations with zero current SET. In addition, island length and its material effect on coulomb blockade and desired current are achieved by decreasing the coulomb blockade range. پرونده مقاله -
دسترسی آزاد مقاله
20 - Adsorption of Vitamin C on a Fullerene Surface: DFT Studies
Rezvan Baniasadi Kun Harismah Maryam Sadeghi Mahmoud MirzaeiDensity functional theory (DFT) calculations were performed to investigate adsorptions of vitamin C (Vit) on the surface a fullerene structure (Ful) in gaseous and water–solvated systems. Two models of Vit including OVit and MVit were created based on the original چکیده کاملDensity functional theory (DFT) calculations were performed to investigate adsorptions of vitamin C (Vit) on the surface a fullerene structure (Ful) in gaseous and water–solvated systems. Two models of Vit including OVit and MVit were created based on the original structure of Vit for OVit and methylation of all hydroxyl groups for MVit. All singular and hybrid structures were optimized and the molecular properties were then evaluated for them. Binding energies and dipole moments indicated that the formation of MVit–Ful hybrid could be more favourable than OVit–Ful hybrid. Molecular orbital properties of hybrid systems demonstrated almost similarity to each other and similarity to the singular Ful model; however, they are completely different from both of singular Vit models. It could be mentioned that the Vit counterparts miss their contributions to molecular orbital distributions in the hybrid systems. Quadrupole coupling constants (CQ) have been also evaluated for oxygen atoms of Vit counterparts in both singular and hybrid models, in which they demonstrated the effects of interactions on the atomic scale properties of Vit counterparts. The evaluated results indicated the solvent effects on all molecular and atomic scales properties of Vit and Ful structures in both of singular and hybrid situations. پرونده مقاله -
دسترسی آزاد مقاله
21 - IR and UV Spectroscopic Analysis of C<sub>20</sub> Carbon Nanostructures
Mehdi Zamani Ahmad Motahari Hossein A. Dabbagh Hossein FarrokhpourInfrared (IR) and ultraviolet (UV) spectroscopic analysis of eight structural isomers of C20 carbon nanostructures, i.e. ring, tadpole, bow-tie, dumb-bell, spiro, propellane, bowl and cage, were performed at different levels of theory including semi-empirical (AM1 and P چکیده کاملInfrared (IR) and ultraviolet (UV) spectroscopic analysis of eight structural isomers of C20 carbon nanostructures, i.e. ring, tadpole, bow-tie, dumb-bell, spiro, propellane, bowl and cage, were performed at different levels of theory including semi-empirical (AM1 and PM3), Hartree-Fock (HF/6-31++G, 6-31++G**) and density functional theory (B3LYP/6-31++G, 6-31++G**). A broad range of IR spectra (400-2700 cm-1) is covered by C-C bending vibrations (low frequency region) and C-C stretching vibrations (high frequency region) in almost all isomers. The absorption maximum (λmax) in UV spectra for bowl and cage isomers appears below 300 nm and for cyclic isomers above it. These results show that IR and UV spectra are useful tools for identification of C20 structural isomers. پرونده مقاله -
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22 - Hydrogen storage capacity of Si-decorated B80 nanocage: firstprinciples DFT calculation and MD simulation
Masoud Darvish Ganji Nasim AhmadianHydrogen storage capacity of Si-coated B80 fullerene was investigated based on density functional theory calculations within local density approximation and generalized gradient approximation. It is found that Si atom prefer to be attached above the center of pentagon w چکیده کاملHydrogen storage capacity of Si-coated B80 fullerene was investigated based on density functional theory calculations within local density approximation and generalized gradient approximation. It is found that Si atom prefer to be attached above the center of pentagon with a binding energy of -5.78 eV. It is inferred that this binding is due to the charge transfer between the Si atom and B80 cage, such as B80AM, B80Ca and B80Mg complexes. The media produced by 12 Si atoms coating on B80, i.e. Si12B80, which Si atoms do not cluster on the B80 surface, can store up to 96 hydrogen molecules resulting in the gravimetric density of 13.87 wt %. Binding of 96 H2 molecules adsorbed on Si12B80 is found to be -0.03 eV/H2 based on the first-principles van der Waals density functional calculations being an indication of the weak interaction (physisorption) between H2 molecules and B80. Furthermore, the adsorption behavior of 96 H2 molecules around the Si12B80 complex was studied through ab initio molecular dynamics simulation at room temperature. Our finding shows that hydrogen molecules escape from the cage, which highlights that the corresponding system easily releases the hydrogen molecules at ambient conditions. پرونده مقاله -
دسترسی آزاد مقاله
23 - The Quest for Sustainable Catalysis through Transition Metal Doped Carbon-based Single-Atom Catalysts
Chamalki Madhusha Madhavi de Silva Imalka Munaweera Chandani Perera Nilwala KottegodaSingle-atom catalysts have recently received much scientific attraction as sustainable catalysts due to their greater activity and selectivity arising from the uniform distribution, electronic properties, and quantum mechanical interactions at the nanoscale of single at چکیده کاملSingle-atom catalysts have recently received much scientific attraction as sustainable catalysts due to their greater activity and selectivity arising from the uniform distribution, electronic properties, and quantum mechanical interactions at the nanoscale of single atoms coupled with interactions at the metal-support interfaces. Carbon-based materials are an excellent support material for single-atom catalysts owing to their inherent properties such as adjustable pore size, high surface area to volume ratio, and ease of surface functionalization. The interactions at the single atom-carbon support interfaces give rise to the extraordinary catalytic activity in carbon-based single metal catalysts thus opening doors for a wide range of sustainable applications. This review focuses on the evolution of carbon-based single-atom catalysis covering different types of carbon substrates, usage of different single atoms with special attention to transition metals, and its wide range of applications including photocatalysis, organic catalysis, and electrocatalysis followed by the future perspectives on carbon-based single-atom catalysts. پرونده مقاله
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