Structure and Stability of M₆N₈ Clusters (M = Si, Ge, Sn, Ti)

Abstract

The structures and stabilities of the M(6)N(8) clusters (M = Si, Ge, Sn, Ti) have been theoretically studied at DFT and ab initio levels of theory. Two new isomers have been considered: cage-like molecules and propeller-like molecules. It is shown that only for M = Si are both isomers true minima on the potential energy surface. The thermodynamics of the dissociation process (1/6)M(6)N(8) --> (1/3)M(3)N(4) is discussed. For each M(3)N(4) molecule, four structures with different multiplicity are considered. The thermodynamic analysis shows that independently of the multiplicity of M(3)N(4) nitrides all M(6)N(8) clusters are stable in the gas phase in a wide temperature range and could be potential intermediates in chemical vapor deposition of the nitride materials.

Boron‐Substituted Coronene: Intriguing Geometric and Electronic Properties, and Large Nonlinear Optical Response

“…To investigate the relative stability of B-coronene with different spin states, the single-point energies of them have been plotted in Figure 6, while the relative energies are presented in Table S2. As the spin-projected MP2 (PMP2) [40] is known to provide energy results less influenced by spin contamination 41 than the UMP2 method for open shell systems, the single-point energies are calculated at the PMP2/6-31 + G(d, p) to minimize the errors caused by the spin contamination. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 From Table S2 and Figure 6, it is noted that the singlet structure is the lowest-energy one among these structures with different spin states for both the pristine and boron-substituted coronene, and the total energies are gradually increased as the spin multiplicity increases.…”

Structural and electronic properties of boron- and nitrogen-doped SinCn(n= 7–15) clusters: a theoretical investigation

“…This may be because the nitrogen atom has three 2p-electrons, which easily form three σ bonds with other neighbour atoms, while the silicon atom has two 3s-and two 3p-electrons, which prefer forming covalent bonds with other atoms by sp 3 hybridization. In this case, the N atom forms threefold coordinated to neighbour Si atoms, which is similar to the atomic configuration character of silicon nitride clusters (such as Si 6 N 8 [43,44] and Si n−1 N [45] clusters). Furthermore, these results show that doping with the N atom leads to significant structural distortion compared with their corresponding pure Si n C n clusters.…”