A computation al ۲۷Al and ۱۵N NMR Charac terization of AlnN n clusters with n= ۱۲, ۱۶, ۲۸, ۳۶ and ۴۸

Numerous efforts have been devoted rece ntly to the s tudy of possible fullerene-like stru ctures constructed of ot her element s rather tha n carbon. E specially, clusters of Groups III–V have emerged as a choice for the next generation materials for applications in the microelectronic and light-emitting diodes [۱]. Theoretica l studies predicted [۲] that the fullerene-like cages AlnNn may be magic clusters having inherent special stability. Wang et al. [۳] suggested these clusters as ideal materials for hydrogen storage app lications un der ambient thermody namic conditions.NMR parameters such as chemical shield ing (CS) tensors, either measured experimentally or reprod uced reliably by perfo rming high-level quantu m chemical calculation s provide h ighly valuab le information about electrostatic environment around th e nucleus, w hich feels subtle changes by any perturbatio ns. This w ork aims at analyzing geometrica l and electronic charac teristic of A lnNn nanoca ges (n= ۱۲, ۱۶, ۲۸, ۳۶ a nd ۴۸) on t he basis of calculated ۱۵ N and ۲۷Al NMR parameters, whic h might be a useful guidance for the experimental studies, see Fig.۱.Comp utational M ethod :Geometries of all systems were fully opti mized at the level of B۳LYP/۶-۳۱+ G* via Gau ssian ۹۸ pa ckage of pro gram. The gauge inclu ding atomic orbital (GI AO) approa ch was applied to calculate chemical shielding. The calcula ted CSI ten sors in the principal ax es system (PAS) (ı۳۳>ı ۲۲>ı۱۱) were used for converting data to measurable NMR para meters: chemical shielding isotropic (CSI), using CSI (pp m) =۱/۳(ı۱۱+ı۲۲+ı۳۳) and CSA (pp m) = ı۳۳- (ı۱۱ + ı۲۲) /۲ .

کلیدواژه ها:

AlN n anocage ، N MR ، DFT