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There is a compelling reason to design cost-effective sensors to detect and measure harmful molecules such as dichlorosilane ($\mathrm{H}_{2}\mathrm{SiCl}_{2}$) in the air. In this work, density functional theory (DFT) has been used to study the nature of the intermolecular interactions between the $\mathrm{H}_{2}\mathrm{SiCl}_{2}$ gas molecule with a single-walled pristine, Al-doped, and Ga-doped boron nitride nanotubes (BNNT, BNAlNT, and BNGaNT, respectively) to investigate their potential in gas-sensing applications. Full-dimensional geometry optimization and adsorption energies were calculated with four functionals: PBE0, M06-2X, ${\omega }$B97XD, and B3LYP-D3 with a 6-311G(d) basis set. We find that the B, Al, or Ga atoms provide the most favorable sites for adsorption of the $\mathrm{H}_{2}\mathrm{SiCl}_{2}$ molecule. The adsorbate is more tightly bound to the surface of the doped rather than of the pristine BNNT nanotubes, demonstrating a larger energy gain due to adsorption. This is due to the fact that $\mathrm{H}_{2}\mathrm{SiCl}_{2}$ interacts with pristine BNNT through weak Van der Waals forces but seemingly has stronger ionic interactions with the doped variants. In general, introducing impurities can improve the selectivity and reactivity of the BNNT toward $\mathrm{H}_{2}\mathrm{SiCl}_{2}$. Among all of the absorbents, we find that BNGaNT exhibits the highest affinity toward $\mathrm{H}_{2}\mathrm{SiCl}_{2}$, and therefore holds a higher potential compared to the rest of the nanotubes investigated here for designing materials for dichlorosilane sensors.

In this investigation, the feasibility of detecting the amantadine (AMD) molecule onto the outer surface of pristine fullerene (C 6 0 ), as well as C 5 9 X (X = Si , Ge, B, Al, Ga, N, P, and As) decorated structures, was carefully evaluated. For achieving this goal, a density functional theory level of study using the HSEH1PBE functional together with a 6-311G(d) basis set has been used. Subsequently, the B3LYP-D3, wB97XD and M062X functionals with a 6-311G(d) basis set were also employed to consider the single point energies. Natural bond orbital (NBO) and the quantum theory of atoms in molecules (QTAIM) were implemented using the B3LYP-D3/6-311G(d) method and the results were compatible with the electronic properties. In this regard, the total density of states (TDOSs), the Wiberg bond index (WBI), natural charge, natural electron configuration, donor–acceptor NBO interactions, and the second-order perturbation energies are performed to explore the nature of the intermolecular interactions. All of the energy calculations and population analyses denote that by adsorbing of the AMD molecule onto the surface of the considered nanostructures, the intermolecular interactions are of the type of strong physical adsorption. Among the doped fullerenes, Ge-doped structure has very high adsorption energy compared to other elements. Generally, it was revealed that the sensitivity of the adsorption will be increased when the AMD molecule interacts with the decorated fullerenes and decrease the HOMO–LUMO band gap; therefore, the change of electronic properties can be used to design suitable nanocarrier. The feasibility of detecting the amantadine molecule onto the outer surface of pristine fullerene, as well as C59X (X = Si, Ge, B, Al, Ga, N, P, and As) decorated structures, was carefully evaluated. Various analyses such as the total density of states, the Wiberg bond order, natural bond orbital, noncovalent interaction, and quantum theory of atom in molecule were performed to shed light on the nature of intermolecular interactions. Results show that the change in electronic properties can be used to design suitable nanocarrier. [ABSTRACT FROM AUTHOR]

The feasibility of detecting the chlorofluoromethane (CFM) onto the outer surface of pristine silicon carbide nanotube (SiCNT), as well as its germanium doped structures (SiCGeNT), was carefully evaluated. Density functional theory level of study using the PBE0 functional together with a 6-311G(d) basis set has been used. Subsequently, the B3LYP, CAM-B3LYP, ωB97XD, and M06-2X functionals with a 6-311G(d) basis set were also employed to consider the single point energies. Natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) were implemented by using the PBE0/6-311G(d) method. The total density of states (TDOSs), Wiberg bond index (WBI), natural charge, natural electron configuration, donor–acceptor natural bond orbital interactions, and the second-order perturbation energies are performed to explore the nature of the intermolecular interactions. All results denote that by adsorbing of the gas molecule onto the surface of the considered nanostructures, the intermolecular interactions are of the type of strong physical adsorption. It was revealed that the sensitivity of the adsorption will be increased when the gas molecule interacts with decorated nanotubes and decrease the HOMO-LUMO band gap; therefore, the change of electronic properties can be used to design suitable nanosensors to detect CFM gas. [ABSTRACT FROM AUTHOR]

The feasibility of detecting a Chlorofluoromethane (CFM) gas molecule on the outer surface of a pristine single‐walled boron nitride nanotube as well as Al‐, Ga‐, P‐, and As‐doped structures. A periodic boundary condition (PBC), within a density functional theory (DFT) method, using the Perdew, Burke, and Ernzerhof exchange‐correlation (PBE0) functional, together with a 6‐311G(d) basis set was used. Subsequently, the B3LYP, CAM−B3LYP, ωB97XD, and M06‐2X functionals were also employed to consider the single point energies. Natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) were implemented by using the PBE0/6‐311G(d). To explore the nature of the intermolecular interactions, density of state (DOS), Wiberg bond index (WBI), natural charge, natural electron configuration, donor–acceptor natural bond orbital interactions, the second‐order perturbation energies tests, and noncovalent interaction (NCI) analysis are performed. The sensitivity of the adsorption will be increased when the gas molecule interacts with decorated nanotubes; therefore, the change of electronic properties can be used to design suitable nanosensors. [ABSTRACT FROM AUTHOR]

The density functional techniques (DFT) were put into practice to study the nature of the intermolecular interactions between Vinyl chloride (VCM) gas molecule with single-walled pristine, Al and Ga-doped boron nitride nanotubes (BNNT, BNAlNT, and BNGaNT, respectively). For performing optimization process, various functionals including PBE0, M06–2X, ωB97XD, and B3LYP-D3 were applied on both of the isolated and complex structures. All of the functionals were used together with split-valence triple-zeta basis sets with d-type Cartesian-Gaussian polarization functions (6-311G(d)). To consider the electronic structure, total density of state (DOS) analysis were employed. Natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), and non-covalent interaction (NCI) analyses were also taken on board to discover the nature of intermolecular interactions between gas and nanotubes. The results of electronic structure calculations as well as population analyses has been carefully tabulated and partially depicted. The HOMO-LUMO energy gap (HLG) were dramatically changed when the dopant atom added to the BNNT. It means the impurity can improve the sensivity and reactivity of the pristine nanotube; therefore, by absorbing the VCM onto the surface of the titled nanotubes, a salient signal can produce in a typical electronic circuit. Among all of the absorbents, BNGaNT shows the most favorable material to design a nanosensor for the studied gas molecule. • The interaction of VCM with BNNT, BNAlNT, and BNGaNT are studied. • To study the adsorption processes, the results of an NBO analysis are analyzed. • To unravel the nature of intermolecular interactions a QTAIM analysis is applied. • NCI analysis were performed to consider the non-covalent interactions. [ABSTRACT FROM AUTHOR]

• The adsorption of CBrClF 2 on to the BNNT, BNAlNT, BNGaNT, BNPNT, and BNAsNT are studied. • To investigare the adsorption processes, the results of an NBO and QTAIM analyses are analyzed. • To find out the nature of intermolecular interactions aRDG diagrams are depicted. Nanostructures such as nanotubes and nanosheets are widely used in the medical industry for drug delivery, prevention, and treatment. These nanostructures are used as sensors or carriers by adsorbing functional groups. In this study, the adsorption rates of the bromochlorodifluoromethane (CBrClF 2) molecule, which is used as an effective gaseous fire suppression agent, onto the outer surfaces of pristine, Al, Ga, P, and As-doped boron nitride nanotubes are investigated. A periodic boundary condition density functional theory method using both Perdew, Burke, and Ernzerhof exchange–correlation (PBEPBE) and B3LYP-D3 functionals together with the 6-311G (d) basis set were used. Subsequently, the B3LYP, CAM-B3LYP, ωB97XD, and M06-2X functionals with the 6-311G (d) basis set were used to consider the single-point energies. Natural bond orbital analysis and the quantum theory of atoms in molecule were considered using the PBEPBE/6-311G (d) method, and the results were compatible with the expected electronic properties, namely the Wiberg bond index, natural charge, natural electron configuration, donor–acceptor natural bond orbital interactions, and second-order perturbation energies. All the calculations and analyses denoted that the adsorption of the CBrClF 2 molecule onto the surfaces of pristine boron nitride nanotubes occurred due to physical adsorption and van der Waals interactions. Among the doped nanotubes, the Al nanotube exhibited the highest adsorption energy compared to the other doped nanotubes. [ABSTRACT FROM AUTHOR]