In the present study we focused on the electronic and structural properties of Na and Mg adsorption on the surface of the (6, 6) armchair SiCNTs. The adsorption energy (Eads), band gap energy (Eg), partial density of state (PDOS), chemical potential (μ), global hardness (η), electrophilicity index (ω), global softness (S), work function values (φ) and work function change (Δφ) are calculated by using DFT methods and B3LYP/6-311++G (d, p) level of theory. Adsorption of Na and Mg atoms on the surface of SiCNTs reduce the gap energy (Eg) of nanotube and so the conductivity and chemical reactivity of nanotube/Na or Mg increase significantly from pristine model. The order of decreasing of the Eg values for the studied systems is: SiCNTs > C-SiC/Mg > Si-SiC/Mg > C-SiC/Na > Si-SiC/Na. On the other hand the work function of the SiCNTs/Na or Mg complex alters significantly from pristine model and consequently the field emission current densities of system enhance. The predicted adsorption energies (Eads) follow the order: Si-SiC/Mg> Si-SiC/Na> C-SiC/Mg> C-SiC/Na. تفاصيل المقالة

In this research, the effects of B, O and B&O−doped on the SO2 gas adsorption on the surface of the (4, 4) armchair AlNNTs are investigated by using DFT method. From optimized structures the geometrical and electrical properties, adsorption energy, gap energy, global hardness, electrical potential, HOMO−LUMO orbitals, density of states (DOS) plots, electrostatic potential (ESP) plots and NMR parameters are calculated and are analyzed. The adsorption energy of the all adsorption models is negative and exothermic in thermodynamic view of point. Doping of B atom increases the adsorption energy of nanotube/SO2 complex, whereas doping O atom decreases the adsorption energy of system. The positive values of ∆N of nanotube/SO2 complex indicate that the charge transfer occur toward to the SO2 gas, which suggests that their electronic properties of system could be notably changed upon chemisorption’s of SO2. The NMR results reveal that the isotropy the electrostatic properties of nuclei are mainly dependent on electronic density at their sites, therefore because of the SO2 gas adsorption, the electronic densities of nuclei and the CS tensors undergo changes. تفاصيل المقالة

By using the density function theory (DFT) the adsorption of nitramine (NH2NO2) molecule on the surface of pristine and Ni functionalized of Gallium nitride nanotube (GaNNTs) is investigated. The adsorption energy of NH2NO2 molecule on the surface of pristine and Ni functionalized GaNNTs is in range ‒6.59 to ‒48.16 Kcal/mol and is physisorption type. The ∆E and ∆H values of the all adsorption models are in range ‒10.34 to ‒47.17 Kcal/mol and ‒13.43 to ‒47.77 Kcal/mol respectively, the negative values of ∆E and ∆H reveal that the adsorption of NH2NO2 molecule on the surface of pristine and Ni functionalized GaNNTs is exothermic. The molecular electronic potential (MEP) indicates that a low electron charge is transferred from the NH2NO2 molecule toward the nanotube ones resulting in the exterior surface of nanotube is rich of electron charge. The HOMO energy of adsorbed models on the pristine GaNNTs is lower than Ni functionalized. تفاصيل المقالة

ABSTRACT The main objective of this work is to investigate the adsorption of Pyrrole 2-carboxylic acid (PCA) from O, N and C sites on the surface of pristine and Ni doped B12N12 nano cage by using density functional theory (DFT). The results of adsorption energy indicate that the adsorption of PCA on the surface of B12N12 and NiB11N12 is exothermic and favorable in thermodynamic viewpoint. Comparison results reveal that adsorption of PCA from O head on the surface of B12N12 nano cage is more favorable than other sites, and the recovery time of this site is 2.72×1022 s. The change percent of gap energy for adsorption of PCA molecule on the surface of pristine B12N12 nano cage is more than Ni doped, thereby the pristine B12N12 nano cage can be a good selected for making PCA sensor. The changes Gibbs free energies in water phase (∆∆G(sol)) for adsorption of PCA from N and C site of PCA on the surface of B12N12 are negative and spontaneous. The atom in molecule (AIM) and reduced density gradient (RDG) results indicate that the adsorption PCA from N and C sites on the surface of B12N12 is strong covalent type, and for other sites is partially covalent bond. تفاصيل المقالة

The aims this work to investigate the effects of (n=1, 2, 3) H+ ions functionalizing on the surface of B12N12 nanocage to detect and adsorb 5-Flucytosine (5-FC) drug using density functional theory at the WB97XD/6-31G(d, p) level of theory using Gaussian 09 software. The calculated results indicate that the adsorption of 5-FC drug on the surface of pristine and nH+ functionalized B12N12 nanocage is exothermic, and adsorption process in the presence of nH+ functionalized is more favorable than the pristine model. The thermodynamic results demonstrate that the adsorption of 5-FC on the surface of nH+ functionalized B12N12 nanocage in both the gaseous phase and in the presence of water or ethanol is spontaneous. The gap energy value of nH+ functionalized of B12N12 nanocage is more than the original value and so the conductivity of the system is lower than the pristine model. The AIM and RDG results confirm that the interaction between 5-FC with B12N12 is noncovalent type. The nonlinear optical (NLO) results show that the polarizability (α) and hyperpolarizability (β) of all adsorption models is in range (202.30 to 214.34 a.u.) and (42.18 to 603.98 a.u.) respectively, the NLO and TD-DFT results demonstrate that the optical properties of nanocage in the presence of 5-FC drug and nH+ functionalized change significantly. These results can be useful for making carrier, delivery, and detection of drugs in the biological system. تفاصيل المقالة