ORIGINAL RESEARCH The analysis of electronic structures, adsorption properties, NBO, QTAIM and NMR parameters of the adsorbed hydrogen sulfide on various sites of the outer surface of aluminum phosphide nanotube: a DFT study Maryam Zaboli • Heidar Raissi Received: 15 October 2014 / Accepted: 14 January 2015 / Published online: 6 February 2015 Ó Springer Science+Business Media New York 2015 Abstract Density functional theory (DFT) calculations at the B3LYP/6-31G* level are performed to investigate the adsorption properties and quantum molecular descriptors of H 2 S adsorbed on the external surface of (6,0) single-walled aluminum phosphide nanotube (AlPNT). The vibrational frequencies and physical properties such as dipole moment, chemical potential, chemical hardness and chemical elec- trophilicity of all studied configurations have been sys- tematically explored. Also, the interaction of H 2 S gas and AlPNT on the basis of five reactivity descriptors such as the overall stabilization energy (DE SE(AB) ), the individual energy change of the acceptor (DE A(B) ), the individual energy change of donor (DE B(A) ), the global electrophi- licity difference of AlPNT and H 2 S gas (Dw) and charge transfer (DN) has been explained. All adsorptions are electronically harmless processes and venial impacts on the energy gap of the AlP nanotube. The natural bond orbital calculations are done to derive natural atomic orbital occupancies. The H 2 S molecule physisorbed on the surface of pristine AlP nanotube with adsorption energy of about -20 kJ/mol. The AIM theory has been also used to examine the properties of the bond critical points: their electron densities and Laplacians. The adsorption energy of H 2 S molecule is not so large to hinder the recovery of the AlPNT, and therefore, the sensor will possess short recovery times. Electronic structures of pristine AlPNT and adsorbed H 2 S gas AlPNT models are examined by DFT calculations of chemical shielding (CS) parameters of 27 Al and 31 P atoms. The isotropic and anisotropic CS parame- ters are divided into layers based on the detection of similar electronic environments by the atomic sites of each layer. Keywords Aluminum phosphide nanotube  Hydrogen sulfide  Density functional theory  NBO  NMR  Density of state Introduction Hydrogen sulfide (H 2 S) is a pollutant that is usually con- sidered as a toxic gas. Inhalation of high concentrations of hydrogen sulfide can be fatal [1, 2]. This gas predominantly attacks the neutral system and major organs such as the liver and kidneys [3–6]. H 2 S is also present as a contami- nant in gas feed streams to be a by-product in the electro welding process. Several researchers have concentrated on the production of hydrogen sulfide adsorbents which are capable to adsorb more H 2 S and can remove it from gas streams [3, 7, 8]. Over the past decade, nanotube surfaces have been the subject of extraordinary activity and survey for using in gas sensors, hydrogen storage devices or for removal of toxic gases [9–11]. The interaction of the gas molecules with the surface of the nanotubes has been examined intensely in the last decade due to the importance of technical and fundamental interests [7, 12]. After dis- covering single-walled carbon nanotubes (SWCNTs) [13], many applications have been reported by scientists, like storage, chemical sensors and electronic devices [14–17]. But SWCNTs have some certain disadvantages which have encouraged scientists to think about modeling and syn- thesizing a substitute for it [18]. Several studies have been recently dedicated to the examination of various types of non-carbon nanotubes [19–22]. Numerous theoretical and experimental studies on stable tubular structures of the counterparts of groups III and V have been reported [10, 23, 24]. The tubular structures of atoms counterparts from groups III and V of the periodic table of elements, e.g., M. Zaboli (&)  H. Raissi Department of Chemistry, University of Birjand, Birjand, Iran e-mail: zaboli_m@birjand.ac.ir 123 Struct Chem (2015) 26:1059–1075 DOI 10.1007/s11224-015-0563-2