The Alkali Metal Interactions with MgO Nanotubes

Beheshtian, Javad,Peyghan, Ali Ahmadi,Bagheri, Zargham,Kamfiroozi, M. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.6

Adsorption of alkali metals (Li, Na, and K) on the surface of magnesium oxide nanotubes (MgONTs) with different diameters was investigated using density functional theory. According to the obtained results, the most stable adsorption site was found to be atop the oxygen atom of the tube surface with adsorption energies in the range of -0.25 to -0.74 eV. HOMO-LUMO gap ($E_g$) of the tubes dramatically decreases upon the adsorption of the alkali metals, resulting in enhancement of their electrical conductivity enhancement. The order of $E_g$ decrement caused by the metal adsorption is as follows: K > Na > Li. The results suggest that the MgONTs were transformed from semi-insulator to semiconductor upon the alkali metal adsorption. Increasing the tube diameter, the HOMO/LUMO gap of the pristine tube is enhanced and adsorption energies of the alkali metals are decreased.

ON THE SECOND APPROXIMATE MATSUMOTO METRIC

Tayebi, Akbar,Tabatabaeifar, Tayebeh,Peyghan, Esmaeil Korean Mathematical Society 2014 대한수학회보 Vol.51 No.1

In this paper, we study the second approximate Matsumoto metric F = ${\alpha}+{\beta}+{\beta}^2/{\alpha}+{\beta}^3/{\alpha}^2$ on a manifold M. We prove that F is of scalar flag curvature and isotropic S-curvature if and only if it is isotropic Berwald metric with almost isotropic flag curvature.

A DFT Study on CO₂ Interaction with a BN Nano-Cage

Baei, Mohammad T.,Peyghan, Ali Ahmadi,Bagheri, Zargham Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Covalent functionalization of a $B_{12}N_{12}$ nano-cage with $CO_2$ molecule has been investigated using density functional theory in terms of energetic, geometric, and electronic property analyses. Results show that besides two physisorption configurations, $CO_2$ preferably tends to perform [2+2] addition on B-N bonds of the cluster which are shared between six-membered and four-membered rings, releasing energy of 14.99 kcal/mol for adsorption of the first $CO_2$ and of 15.45 kcal/mol for the second one (per each molecule). On the basis of calculated density of states, we have found that the electronic properties of the physisorbed $B_{12}N_{12}$ by $CO_2$ have not changed, while slight changes have been predicted in the functionalized cases. Present results might be helpful to provide an effective way to modify the $B_{12}N_{12}$ properties for further purifications and applications.

The Alkali Metal Interactions with MgO Nanotubes

Javad Beheshtian,Ali Ahmadi Peyghan,Zargham Bagheri,M. Kamfiroozi 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.6

Adsorption of alkali metals (Li, Na, and K) on the surface of magnesium oxide nanotubes (MgONTs) with different diameters was investigated using density functional theory. According to the obtained results, the most stable adsorption site was found to be atop the oxygen atom of the tube surface with adsorption energies in the range of −0.25 to −0.74 eV. HOMO-LUMO gap (Eg) of the tubes dramatically decreases upon the adsorption of the alkali metals, resulting in enhancement of their electrical conductivity enhancement. The order of Eg decrement caused by the metal adsorption is as follows: K > Na > Li. The results suggest that the MgONTs were transformed from semi-insulator to semiconductor upon the alkali metal adsorption. Increasing the tube diameter, the HOMO/LUMO gap of the pristine tube is enhanced and adsorption energies of the alkali metals are decreased.

Theoretical Study of Thiazole Adsorption on the (6,0) zigzag Single-Walled Boron Nitride Nanotube

Moradi, Ali Varasteh,Peyghan, Ali Ahmadi,Hashemian, Saeede,Baei, Mohammad T. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

The interaction of thiazole drug with (6,0) zigzag single-walled boron nitride nanotube of finite length in gas and solvent phases was studied by means of density functional theory (DFT) calculations. In both phases, the binding energy is negative and presenting characterizes an exothermic process. Also, the binding energy in solvent phase is more than that the gas phase. Binding energy corresponding to adsorption of thiazole on the BNNT model in the gas and solvent phases was calculated to be -0.34 and -0.56 eV, and about 0.04 and 0.06 electrons is transferred from the thiazole to the nanotube in the phases. The significantly changes in binding energies and energy gap values by the thiazole adsorption, shows the high sensitivity of the electronic properties of BNNT towards the adsorption of the thiazole molecule. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of LUMO, electron density, and length of the surrounding bonds of adsorbing atoms help to the thiazole adsorption on the nanotube. Decrease in global hardness, energy gap and ionization potential is due to the adsorption of the thiazole, and consequently, in the both phases, stability of the thiazole-attached (6,0) BNNT model is decreased and its reactivity increased. Presence of polar solvent increases the electron donor of the thiazole and the electrophilicity of the complex. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications.

On the second approximate Matsumoto metric

Akbar Tayebi,Tayebeh Tabatabaeifar,Esmaeil Peyghan 대한수학회 2014 대한수학회보 Vol.51 No.1

In this paper, we study the second approximate Matsumoto metric F = α+β+β2/α+β3/α2 on a manifold M. We prove that F is of scalar flag curvature and isotropic S-curvature if and only if it is isotropic Berwald metric with almost isotropic flag curvature.

A DFT Study on CO2 Interaction with a BN Nano-Cage

Mohammad T. Baei,Ali Ahmadi Peyghan,Zargham Bagheri 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Covalent functionalization of a B12N12 nano-cage with CO2 molecule has been investigated using density functional theory in terms of energetic, geometric, and electronic property analyses. Results show that besides two physisorption configurations, CO2 preferably tends to perform [2+2] addition on B-N bonds of the cluster which are shared between six-membered and four-membered rings, releasing energy of 14.99 kcal/mol for adsorption of the first CO2 and of 15.45 kcal/mol for the second one (per each molecule). On the basis of calculated density of states, we have found that the electronic properties of the physisorbed B12N12 by CO2 have not changed, while slight changes have been predicted in the functionalized cases. Present results might be helpful to provide an effective way to modify the B12N12 properties for further purifications and applications.

Theoretical Study of Thiazole Adsorption on the (6,0) zigzag Single-Walled Boron Nitride Nanotube

Ali Varasteh Moradi,Ali Ahmadi Peyghan,Saeede Hashemian,Mohammad T. Baei 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

The interaction of thiazole drug with (6,0) zigzag single-walled boron nitride nanotube of finite length in gas and solvent phases was studied by means of density functional theory (DFT) calculations. In both phases, the binding energy is negative and presenting characterizes an exothermic process. Also, the binding energy in solvent phase is more than that the gas phase. Binding energy corresponding to adsorption of thiazole on the BNNT model in the gas and solvent phases was calculated to be −0.34 and −0.56 eV, and about 0.04 and 0.06 electrons is transferred from the thiazole to the nanotube in the phases. The significantly changes in binding energies and energy gap values by the thiazole adsorption, shows the high sensitivity of the electronic properties of BNNT towards the adsorption of the thiazole molecule. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of LUMO, electron density, and length of the surrounding bonds of adsorbing atoms help to the thiazole adsorption on the nanotube. Decrease in global hardness, energy gap and ionization potential is due to the adsorption of the thiazole, and consequently, in the both phases, stability of the thiazole-attached (6,0) BNNT model is decreased and its reactivity increased. Presence of polar solvent increases the electron donor of the thiazole and the electrophilicity of the complex. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications.