Narrow Results

Due to the increasing demand of Al${}_{12}$N${}_{12}$ in optoelectronics and sensing materials, we intended to investigate the adsorption behavior, electronic nature and NLO response of hydrogen and different metals decorated Al${}_{12}$N${}_{12}$ nanocages. Different systems are designed by hydrogen adsorption and encapsulation of metals (Li, Na and K) in Al${}_{12}$N${}_{12}$. Density functional theory at B3LYP functional with conjunction of 6-31G($d$, $p)$ basis set is utilized in order to gain optimized geometries. Different calculations including linear and first-order hyperpolarizability are conducted at same level of theory. Instead of chemiosorption, a phyisosorption phenomenon is seen in all hydrogen adsorbed metal encapsulated Al${}_{12}$N${}_{12}$ nanoclusters. The $Q_{\text{NBO}}$ analysis confirmed the charge separation in hydrogen adsorbed metal encapsulated nanocages. Molecular electrostatic potential (MEP) analysis cleared the different charge sites in all the systems. Similarly, frontier molecular orbitals analysis corroborated the charge densities shifting upon hydrogen adsorption on metal encapsulated AlN nanocages. HOMO–LUMO band gaps suggest effective use of H₂-M-AlN in sensing materials. Global indices of reactivity also endorsed that all hydrogen adsorbed metal encapsulated systems are better materials than pure Al${}_{12}$N${}_{12}$ nanocage for sensing applications. Lastly, linear and first hyperpolarizability of H₂-M-AlN nanocages are found to be greater than M-AlN and pure AlN nanocages. Results of these parameters recommend metal encapsulated nanocages as efficient contributors for the applications in hydrogen sensing and optoelectronic devices.

Recently the three-dimensional structure of verdoheme heme oxygenase complex was revealed. However, many parameters of verdoheme heme oxygenase’s complex structure and their role and function on Heme degradation were unknown. In this work the structure of iron verdoheme in complex with heme oxygenase was compared by the density functional theory (DFT)-based B3LYP method using the 6-31G basis set. Many parameters such as charge of verdoheme and iron as central metal, electron distribution, spin multiplicity of the molecule and proximal substituents effects on verdoheme ring stabilization and their arrangement are discussed and compared for twelve different conformations of the molecules to find the most energetically stable states.

Gas sensing materials have been widely explored recently owing to their versatile environmental and agriculture monitoring applications. Phosgene (COCl₂) is a toxic and harmful gas, therefore, a reliable and sensitive technique is required for monitoring its quantity in the atmosphere. In this study, pure as well as copper decorated B${}_{12}$P${}_{12}$(Cu-BP) nanoclusters were analyzed using DFT method to investigate their specific potential for phosgene gas adsorption. Cu interaction resulted in three optimized geometries S1, S2 and S3 with interaction energies of $-$234.52kJ/mol, $-$214.59kJ/mol and $-$266.45kJ/mol, respectively. In all these three cases, the COCl₂ prefers to interact at the top of the cage. The phosgene molecule (COCl₂) interacts with bare nanocage at a distance of 3.22Å with interaction energy of $-$6.22kJ/mol, while the observed interaction energies of phosgene at Cu decorated B${}_{12}$P${}_{12}$ are $-$76.90kJ/mol, $-$119.03kJ/mol and $-$29.60kJ/mol, respectively. To observe the variations in electronic structure, fermi level, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), natural bonding orbital ($Q_{\mathrm{\text{NBO}}}$), softness, hardness, chemical potential and electrophilicity are calculated before and after phosgene adsorption. Energy gap reduce significantly after phosgene adsorption from 2.31eV, 2.05eV and 2.46eV to 1.54eV, 1.57eV and 2.45eV, respectively. Results of all analysis suggested that decoration of Cu significantly enhanced the adsorption power of B${}_{12}$P${}_{12}$ nan-cluster for COCl₂ molecule. Therefore, the Cu-decorated B${}_{12}$P${}_{12}$ nanocages are considered as potential candidates for application in COCl₂ sensors.