فهرس المقالات chemical hardness

• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  1 - Investigation of relationship with electron configuration of chemical hardness, absolute electronegativity and electrophilicity
  Savas, Kaya Cemal Kaya
  Chemical hardness (), absolute electronegativity (), and electrophilicity () have importantapplications in inorganic chemistry. These concepts are defined quantitatively as � � �� � ����,� � �� � ����, � � ������Where I is the ionization energy and A is the electron أکثر

  Chemical hardness (), absolute electronegativity (), and electrophilicity () have importantapplications in inorganic chemistry. These concepts are defined quantitatively as � � �� � ����,� � �� � ����, � � ������Where I is the ionization energy and A is the electron affinity. In thisstudy, graphical method was used to see the relation of electron configuration with chemicalhardness, absolute electronegativity and electrophilicity. For this purpose, sequential ionization ofatoms were considered. In this method, chemical hardness, absolute electronegativity, electrophilicityand effective nuclear charge (Z*) were calculated for all ions formed with sequential ionization of anatom and chemical hardness, absolute electronegativity and electrophilicity with respect to effectivenuclear charge were illustrated in the graphs. Besides, the same charged ions were considered inorder to see more clearly relationship with electron configuration of these three features becausecharge is effective on chemical hardness, absolute electronegativity and electrophilicity. Likewise,chemical hardness, absolute electronegativity and electrophilicity values were calculated and graphsof these three features were plotted with respect to atomic number (Z). As to conclude, it was proventhat chemical hardness, absolute electronegativity and electrophilicity increase in some specificelectron configurations and this means that configuration effect is a more effective factor than radiusand charge. تفاصيل المقالة
• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  2 - Derivation of ionization energy and electron affinity equations using chemical hardness and absolute electronegativity in isoelectronic series
  S. Kaya C. Kaya
  Chemical hardness () and absolute electronegativity () have important applications in chemistry. Inthe conceptual Density Functional theory (DFT), these concepts has been associated with electronicenergy and the relationship with ionization energy (I) and electron aff أکثر

  Chemical hardness () and absolute electronegativity () have important applications in chemistry. Inthe conceptual Density Functional theory (DFT), these concepts has been associated with electronicenergy and the relationship with ionization energy (I) and electron affinity (A) of these concepts hasbeen given. In this study, graphical method was used in order to see the relationship with the atomicnumber (Z) of chemical hardness and absolute electronegativity in isoelectronic series. These serieswas considered because all members of an isoelectronic series have the same shielding constant.Chemical hardness and electronegativity equations depending on atomic number were obtained fromgraphs of =f(Z) and =f(Z) for isoelectronic series that contain electron from 1 to 20. Ionizationenergy and electron affinity equations were obtained making use from the chemical hardness andelectronegativity equations. In the last stage, the relationship with the number of electron ofcoefficients in the ionization energy and electron affinity equations was examined. As a result, newequations consistent with experimental results that depending on atomic number and number ofelectron were obtained. تفاصيل المقالة
• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  3 - Computational study of chemical properties of Captopril drug and the connected form to Fullerene (C60) as a medicine nano carrier
  Roya Ahmadi
  In this research at the first, captopril drug (CA) and its fullerene connected form (FCA) wereoptimized. Natural Bond Orbital (NBO) calculations for these compounds were carried out at theB3LYP/6-31G quantum chemistry level, in the gas phase and the liquid phase. These أکثر

  In this research at the first, captopril drug (CA) and its fullerene connected form (FCA) wereoptimized. Natural Bond Orbital (NBO) calculations for these compounds were carried out at theB3LYP/6-31G quantum chemistry level, in the gas phase and the liquid phase. These calculations canbe performed at different accuracy levels depending on the aim of the theoretical study [1]. Forinstance, Density Functional Theory (DFT) can be used to calculate an accurate electronic structure,HOMO and LUMO energies, Mulliken charge of atoms, energetic_orbital levels, chemical hardness,chemical potential and electrophilicity of systems, and finally chemical, physical, biological,pharmacological and industrial of fullerene and fullerene derivatives [47]. Theoretical calculationssuch as NBO are very important to understand the pathways of electron transfer in assemblies.Consequently, the obtained results showed that energy orbital levels decreased considerably bylinking structure of Captopril to structure of fullerene C60. In the study some other characteristicssuch as chemical potential, chemical hardness, electrophilicity in these structures; it was found thatthey changed considerably. These changes show dependency of the results, on power of electronaffinity of C60. In another part, the valence electrons populations for carbons, nitrogen, oxygens andhydrogens atoms in similar position for FCA and CA were compared. Finally the data were comparedand discussed. تفاصيل المقالة
• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  4 - Efficiency Measurement in Two-Stage Network Structures Considering Undesirable Outputs
  AR. Amirteimoori A. Tolooei Eshlaghi‎ M. Homayounfar
  Data envelopment analysis (DEA) has been proven as an excellent data oriented nonparametric technique to evaluate the relative performance of peer decision making units. Since DEA is introduced in 1978, it has been widely applied to measure the efficiency of a wide va أکثر

  Data envelopment analysis (DEA) has been proven as an excellent data oriented nonparametric technique to evaluate the relative performance of peer decision making units. Since DEA is introduced in 1978, it has been widely applied to measure the efficiency of a wide variety of production and operation systems. Recently DEA has been extended to examine the efficiency of decision making units (DMUs) with two-stage network structures or processes, where the outputs from the first stage are intermediate measures that make up the inputs of the second stage. Many researchers developed several DEA based models for evaluating the efficiencies of such systems. This paper considers the performance evaluation of the general two-stage network structures, while each stage may produce undesirable outputs (bad outputs), in addition to desirable and goos outputs. The applicability of the approach in this paper is illustrated by using the Green Hen poultry chain data in Guilan province, Iran. تفاصيل المقالة
• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  5 - A computational study on Gauche Effect of C8H15O-X (X: OH, NH2, CH3) Conformers
  Ghazaleh Kouchakzadeh
  Theoretical calculations of chemical hardness and stability energy on C8H15O-X (X: OH, NH2, CH3) carried out by NBO at the B3LYP/6-311+G** level. C8H15O-X have been two distinguishable conformations: one CO-anti position, and the other CO-gauche position. This calculati أکثر

  Theoretical calculations of chemical hardness and stability energy on C8H15O-X (X: OH, NH2, CH3) carried out by NBO at the B3LYP/6-311+G** level. C8H15O-X have been two distinguishable conformations: one CO-anti position, and the other CO-gauche position. This calculations confirm importance of LP2O16→ σ*C12-Y(Y=O, N, C) hyperconjugation interactions that can stable the CO-gauche conformers. Chemical hardness of CO-gauche conformers is in good agreement with the energy results. This results show that molecular interaction in the gauche geometries increases from compound with X=OH to X=CH3. Actually, the gauche effect with hyperconjugation factor play important role in the stability of the gauche geometries. تفاصيل المقالة
• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  6 - The Substituent Effects on Chemical Reactivity and Aromaticity Current of Ritalin Drug
  Arezoo Tahan Mahya Khojandi
  10.22034/jchr.2021.1929266.1303
  In this study, the effects of four substitutions in two different positions of Methylphenidate (MPH, Ritalin) structure on chemical reactivity indices and aromaticity current of benzene ring were investigated at the density functional theory (DFT) level. The results wer أکثر

  In this study, the effects of four substitutions in two different positions of Methylphenidate (MPH, Ritalin) structure on chemical reactivity indices and aromaticity current of benzene ring were investigated at the density functional theory (DFT) level. The results were interpreted using natural bond orbital (NBO) analysis. The findings indicated that by increasing the participation of the studied substitutions in intramolecular interactions, their effect on the chemical reactivity indices and aromaticity current increased. Therefore, the substituents NO2 and Cl on the benzene ring, with the highest participation in intramolecular interactions, caused the highest increase in the resonance interactions of the benzene ring. As a result, they increased the values of the Nuclear Independent Chemical Shift (NICS) in the geometric center of the ring. Also, the above substitutions decreased the energy gap between HOMO (highest occupied molecular orbitals) orbitals and LUMO (lowest unoccupied molecular orbitals) and increased chemical reactivity indices. On the other hand, The NBO results represented that electron-withdrawing substituents at positions R7 and R9 reduced the accumulation of negative charge on adjacent atoms and the benzene ring. تفاصيل المقالة