Ab Initio Investigation of Structures and Energies of Low-Lying Electronic States of AlN₃, Al₃N, and Al₂N₂

Abstract

The structures and energies of low-lying electronic states of AlN3, Al3N, and Al2N2 have been evaluated at the HF, MP2, QCISD(T), CCSD, and CCSD(T) levels of theory, using the several basis sets of 6-31G* (for HF), cc-pVDZ (for MP2 and QCISD(T)), and cc-pVTZ (for CCSD and CCSD(T)). The ground state of AlN3 is predicted to be a 1Σ+ state with a linear Al−N−N−N structure. The most stable species of Al3N is found, however, to have D 3 h symmetry and 1A‘1 ground state. For Al2N2, various isomers are found to be energetically favorable. A rhombic isomer with the nitrogen atoms along the short diagonal and with a 1Ag electronic state is the lowest in energy at the MP2/cc-pVDZ, QCISD(T)/cc-pVDZ, CCSD/cc-pVTZ, and CCSD(T)/cc-pVTZ levels. A linear structure Al−N−N−Al with a 3 electronic state is the second lowest. The third stable isomer with the aluminum atoms bonded directly to the N2 π orbital seems to be one of the model species for the sake of the nitrogen fixation. Our results suggest that the formation of a variety of the configuration of Al2N2 is energetically plausible under the reaction conditions employed since the energy differences in the Al2N2 species are relatively small.

Surface bonding effects in compound semiconductor nanoparticles: II

“…GaAs clusters have been modeled by various groups including Chelikowsky and coworkers (15,16) and others (17)(18)(19)(20)(21)(22)(23)(24)(25). GaN clusters have also been studied by Pandey and coworkers (26)(27)(28) as well as others (29)(30)(31)(32). AlP has also been studied by a number of investigators (33)(34)(35)(36)(37).…”

Reactions of liquid and solid aluminum clusters with N2: The role of structure and phase in Al114+, Al115+, and Al117+

“…29 For Al 44 +/− the secondary products are dominant at high cluster temperatures, in contrast, for Al 114 + , Al 115 + , and Al 117 + the secondary products never amount to more than a few percent of the Al n N 2 + product. For the Al n−3 N + product mentioned above, the corresponding neutral product is probably Al 3 N (Al 3 N is known to be a stable aluminum/nitrogen cluster 41,42 ). The observation of this product indicates that the aluminum clusters can cleave the N 2 bond.…”

Electronic structure and physical properties of MiXi clusters (M = B, Al; X = N, P; i = 1, 2, 3): Ab initio study

“…The CASSCF/MRCI 44(a-c) and CCSD(T) 45 methods served as a benchmark for the inexpensive DFT approach. As to CASSCF/ MRCI, the (8,8) active space was chosen, which seems to be appropriate for most structures studied in this work. If a different active space was used, it is stated explicitly.…”

“…Wavenumbers 1/ were calculated at the MRCI (8,8)/cc-pVQZ level, the oscillator strength f were obtained using the CASSCF (8,8)/cc-pVQZ approach. In case of trimers, (8,7) active space was employed. The isomers are denoted by geometry number corresponding to Figures 1 and 4.…”