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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 paper, we have theoretically determined the possibility of adsorption of the gaseous C[H.sub.2][N.sub.2] molecule on the surface of [X.sub.12][Y.sub.12] nanocages, where X = B, Al, Ga and Y = N, P, As. The electronic structure calculations have been performed by density functional theory (DFT) using four functionals (i.e., B3LYP-D3, M06-2X, [omega]B97XD, and CAM-B3LYP), together with the 6-311G(d) basis function. We find that the adsorption of C[H.sub.2][N.sub.2] on top of the X-Y bond of the nanocage is the most preferred site for adsorption. The adsorption process is accompanied by a charge-transfer phenomenon, which results in a strong bond between the terminal N atom of diazomethane and the X atom of the nanocage. This gives rise to significant changes in the highest and lowest occupied molecular orbital (HOMO and LUMO, respectively) energies and thus attribute properties to the nanocages that enable them to act as building blocks of C[H.sub.2][N.sub.2] sensing materials. Key words: diazomethane, nanocage, DFT, NBO, QTAIM. Dans le cadre des présents travaux, nous avons réalisé une étude théorique pour déterminer la possibilité d'adsorption de la molécule de diazométhane (C[H.sub.2][N.sub.2]) gazeux à la surface de nanocages de formule [X.sub.12][Y.sub.12], où X = B, Al, Ga et Y = N, P, As. Nous avons modélisé la structure électronique selon des calculs de la théorie de la fonctionnelle de la densité (DFT), dans lesquels nous avons utilisé quatre fonctionnelles (soit B3LYPD3, M062X, xB97XD et CAMB3LYP) ainsi que la base 6311G(d). Nos résultats montrent que la liaison X-Y de la nanocage est le site d'adsorption privilégié du C[H.sub.2][N.sub.2]. Le processus d'adsorption est accompagné d'un phénomène de transfert de charge, qui se traduit par une forte liaison entre l'atome d'azote terminal du diazométhane et l'atome X de la nanocage. Ce phénomène donne lieu à des changements importants dans les énergies des orbitales moléculaires frontières (HOMO et LUMO) et confère donc aux nanocages des propriétés qui en font d'éventuels constituants de base pour former des matériaux de détection du C[H.sub.2][N.sub.2]. [Traduit par la Rédaction] Mots-clés : diazomethane, nanocage, théorie de la fonctionnelle de la densité, orbitales naturelles de liaison, théorie quantique des atomes dans les molecules., 1. Introduction Diazomethane (C[H.sub.2][N.sub.2])--ahighly toxic, flammable, and corrosive gas in its pure form at room temperature--can have a number of severe effects upon human health. (1) For example, inhalation of [...]

In the present investigation, the feasibility of detecting the 1-chloro-1,2,2,2-tetrafluoroethane gas molecule on the outer surface of pristine single-walled boron nitride nanotube, as well as its aluminium- and gallium-doped structures, was carefully evaluated. For achieving this goal, a periodic boundary condition density functional theory level of study using both HSE06 and B3LYP-D3 functionals together with a 6-311G(d) basis set has been used. Subsequently, the CAM-B3LYP, xB97XD, and M06-2X functionals with a 6-311G(d) basis set were also employed to consider the single point energies. Natural bond orbital and quantum theory of atoms in molecules were implemented by using the HSE06/6-311G(d) method and the results were compatible with the electronic properties. In this regard, the total density of state, the Wiberg bond index, 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 of the energy calculations and population analyses show that by adsorbing of the gas molecule onto the surface of the considered nanostructures, the intermolecular interactions are of the type of strong chemical adsorption. Between the doped nanotubes, aluminium-doped nanotube has very high adsorption energy compared with gallium. Generally, 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. Key words: 1-chloro-1,2,2,2-tetrafluoroethane, HCFC-124, freon 124, boron nitride, density functional theory, natural bond orbital. Dans la presente etude, nous avons evalue en detail la faisabilite de la detection de la molecule gazeuse de 1chloro-1,2,2,2-tetrafluoroethane sur la surface externe d'un nanotube de nitrure de bore pur a simple paroi, ainsi que sur les structures analogues dopees a l'aluminium et au gallium. Pour ce faire, nous avons employe des conditions aux limites periodiques appliquees a la theorie de la fonctionnelle de la densite a un niveau theorique utilisant les fonctionnelles HSE06 et B3LYPD3 avec la base 6311G(d). Par la suite, nous avons egalement utilise les fonctionnelles CAMB3LYP, xB97XD et M062X avec la base 6311G(d) pour tenir compte des energies ponctuelles. Nous avons fait appel a la theorie de l'orbitale naturelle de liaison et a la theorie des atomes dans les molecules en utilisant la methode HSE06/6311G(d) et nous avons observe une concordance des resultats avec les proprietes electroniques. A cet egard, nous avons calcule la densite totale de l'etat, l'indice de liaison de Wiberg, la charge naturelle, la configuration electronique naturelle, les interactions donneur-accepteur des orbitales naturelles de liaison et les energies de perturbation de second ordre afin d'explorer la nature des interactions intermoleculaires. Tous les calculs d'energie et toutes les analyses de population indiquent que lorsque la molecule de gaz s'adsorbe sur la surface des nanostructures que nous avons etudiees, les interactions intermoleculaires sont du type d'adsorption chimique forte. Entre les nanotubes dopes, celui dope a aluminium presente une energie d'adsorption tres elevee par rapport a celui dope au gallium. De maniere generale, les resultats revelent que la sensibilite de l'adsorption sera accrue lorsque la molecule de gaz interagit avec des nanotubes decores et que l'ecart entre les bandes HOMOLUMO sera reduit. Par consequent, ce changement des proprietes electroniques peut etre mis a contribution pour concevoir des nanocapteurs fonctionnels. Mots-cles : 1-chloro-1,2,2,2-tetrafluoroethane, HCFC-124, freon 124, nitrure de bore, theorie de la fonctionnelle de la densite, orbitale naturelle de liaison., Introduction Nanotubes are structurally divided into carbon and non-carbon nanotubes. Carbon nanotubes (CNTs) were first discovered independently by Iijima and Ichihashi in 1991 in soot from carbon discharge in a [...]

We have investigated the potential energy curves (PECs) of the LiN heteronuclear diatomic molecule, including its ionic species LiN+ and LiN−, using explicitly correlated multi‐reference configuration interaction (MRCI‐F12) calculations in conjunction with the correlation consistent quintuple‐휁 basis set. The effect of core–valence correlation, scalar relativistic effects, and the size of the basis sets has been investigated. A comprehensive set of spectroscopic constants determined based on the above‐mentioned calculations are also reported for the lowest electronic states and all systems, including dissociation energies, harmonic and anharmonic vibrational frequencies, and rotational constants. Additional parameters, such as the dipole moments, equilibrium spin‐orbit constants, excitation energies, and rovibrational energy levels, are also documented. We found that the three triplet states of LiN, namely, X 3∑−, A 3Π, and 2 3∑−, exhibit substantial potential wells in the PEC diagrams, while the quintet states are repulsive in nature. The ground state of the anion also shows a deep potential well in the vicinity of its equilibrium geometry. In contrast, the ground and excited states of the cation are very loosely bound. Charge transfer properties of each of these states are also analyzed to obtain an in‐depth understanding of the interatomic interactions. We found that the core–valence correlation has a substantial effect on the calculated spectroscopic constants. [ABSTRACT FROM AUTHOR]

The study of intermolecular interactions is of great importance. This study attempted to quantitatively examine the interactions between bromine monochloride (BrCl) with pristine boron nitride nanotube (BNNT) armchair (5,5) and zigzag (7,0) as well as armchair (5,5) BC2NNT and zigzag (7,0) BC2NNT in vacuum. Quantum mechanical studies of such systems are possible in the density functional theory (DFT) framework. For this purpose, various functionals, such as B3LYP-D3, ω B97XD, and M062X, have been used. One of the most suitable basis functionals for the systems studied in this research is 6-311G (d), which has been used in both optimization calculations and calculations related to wave function analyses. The main part of this work is the study of various analyses that reveal the nature of the intermolecular interactions between the two components introduced above. The results of conceptual DFT, natural bond orbital, non-covalent interactions, and quantum theory of atoms in molecules (QTAIM) were consistent and in favor of physical adsorption in all systems. Gallium had more adsorption energy than other dopants. The HOMO–LUMO energy gaps were as follows: BNNT (5,5): 10.296, BNNT (7,0): 9.015, BC2NNT (5,5): 7.022, and BC2NNT (7,0): 5.979 eV at B3LYP-D3/6-311G (d) model chemistry. The strongest interaction is related to the BC2NNT (7,0)/BrCl cluster: − 0. 4 8 8 eV. The results of QTAIM and NCI analysis identified the intermolecular interactions of the type of strong van der Waals interaction for these nanotubes. The sensitivity of the adsorption increased when a gas molecule interacted with carbon-doped BNNT, and the change in the frontier orbital gap could be used to design nanosensors to detect BrCl gas. The interactions between BrCl with BNNT) armchair (5,5) and zigzag (7,0) as well as armchair (5,5) BC2NNT and zigzag (7,0) BC2NNT were studied. The sensitivity of the adsorption increased when the gas molecule interacted with carbon doped BNNT. The results of conceptual DFT, NBO, NCI, and QTAIM analyses were consistent and in favor of physical adsorption in all systems. [ABSTRACT FROM AUTHOR]

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]

Context: This research investigates two critical areas, providing valuable insights into the properties and interactions of boron nitride nanotubes (BNNTs). Initially, a variety of BNNT structures (BNNT(m,n)_x, where m = 3, 5, 7; n = 0, 3, 5, 7; x = 3-9) with different lengths and diameters are explored to understand their electronic properties. The study then examines the interactions between these nanotubes and several gases (CO, CO 2 , CSO, H 2 O, N 2 O, NO, NO 2 , O 2 , ONH, and SO 2 ) to identify the most stable molecular configurations using the bee colony algorithm for global optimization. The primary findings highlight the impact of nanotube diameter on these properties. It was observed that smaller diameters result in a larger energy gap due to increased quantum confinement. Significant charge transfer, especially with CO, was detected, affecting the electronic structure of the nanotubes. The study highlighted that BNNTs exhibit the strongest adsorption tendencies for NO₂, O₂, and SO₂. These findings underscore the critical roles of nanotube diameter and charge transfer in sensor applications and demonstrate the comprehensive utility of various analytical methods in understanding BNNT-gas interaction mechanisms., Methods: The research employs a comprehensive computational framework based on density functional theory (DFT). Various DFT methods, such as PBE0, B3LYP(GD3BJ), CAM-B3LYP, HSE06i, M06-2X, and ωB97XD functionals, are utilized along with the Def2tzvp basis set for the calculations. Structural optimizations are performed to ensure accuracy, and modifications to the energy gaps are analyzed using conceptual DFT. Additionally, Total Density of States (TDOS) analyses are conducted. Charge transfer mechanisms are investigated through Natural Bond Orbital (NBO) analysis. The interactions between gases and nanotubes are characterized at critical points using the Quantum Theory of Atoms in Molecules (QTAIM) framework., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The present investigation delves into the adverse environmental impact of atmospheric pollutant gases, specifically nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ), which necessitates the identification and implementation of effective control measures. The central objective of this study is to explore the eradication of these pollutants through the utilization of aluminum Al 13 and Al 15 metal clusters, distinguished by their unique properties. The comprehensive evaluation of gas/cluster interactions is undertaken employing density functional theory (DFT). Geometric optimization calculations for all structures are executed using the ωB97XD functional and the Def2-svp basis set. To probe various interaction modalities, gas molecule distribution around the metal clusters is sampled using the bee colony algorithm. Frequency calculations employing identical model chemistry validate the precision of the optimization calculations. The quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) methodologies are applied for the analysis of intermolecular interactions. This research establishes the robust formation of van der Waals attractions between the investigated gas molecules, affirming aluminum metal clusters as viable candidates for the removal and control of these gases., Competing Interests: There is no conflict of interest for this manuscript., (This journal is © The Royal Society of Chemistry.)