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Using a genetic algorithm together with DFT computations, the stable isomers of Lin+1Fn (n = 2 ~ 17) are obtained. It is found that the Li3F2 is a planar structure, and starting at n = 3, Lin+1Fn adopt three-dimensional configurations with a terminal Li atom or vacancy of F atom. As the cluster sizes increase, the geometries of Lin+1Fn develop, first with cube-like and tubular structures, then forming cage-like arrangements, and eventually favoring rock-salt configurations. The Lin+1Fn (n = 3, 5, 8, 11, 13 and 15) are especially stable and magic number clusters. Low ionization potentials are acquired for Lin+1Fn due to the weakly bonded odd electrons of Li atoms. Particularly, the AIP/VIP for Li14F13 and Li17F16 are only 2.68/2.75 eV and 2.77/2.97 eV, respectively, which indicate that they can be looked as superalkali clusters. Meanwhile, the particularly large hyperpolarizabilities (3237157.14 a.u. and 716489.10 a.u.) for these two isomers are also obtained. According to the electronic structure analysis, Li atoms donate their 2s electrons to the 2p orbitals of F atoms, forming Li–F ionic bonds. Additionally, the spectral properties and the reactivities for the magic number clusters are further investigated. [ABSTRACT FROM AUTHOR]

Mo13 is a magic number cluster of Mon and can effectively activate N2 in ammonia synthesis, but its ground-state structure is not determined. The possible stable isomers of Mo13 are obtained by using global searching method (genetic algorithm) and further optimized at the level of BP86/def2-TZVP. The results indicate that Mo13 prefers to adopt open or layer-type structures due to the stronger 4d-5 s orbital hybridization. The most stable structure of Mo13 is a seriously deformed icosahedron and it is nearly degenerated in energies with the isomer of cage-like one. Both these two isomers are with high stabilities, and thus the electronic structures, bonding characters, spectral properties, reactive activities and the external filed response for these two isomers are systematically explored. This work provides many important information for distinguishing these two isomers. [ABSTRACT FROM AUTHOR]

The stable isomers of (LiF)n (n = 2∼18) are obtained by using genetic algorithm combined with DFT calculations. Both the (LiF)2 and (LiF)3 are planar structures, and from n = 4, the three-dimensional structures become more energy favored. The cage-like isomers are dominated for n = 4∼12. However, (LiF)9 and (LiF)15 adopt tubular configurations, while (LiF)16 and (LiF)18 form rock-salt structures. (LiF)n (n = 2, 4, 6, 9, 12 and 15) can be considered as magic number clusters and particularly stable. There is small vertical electron affinity but large vertical ionization potential for (LiF)n. The electronic structure analysis indicates that Li atoms transferred their 2 s electrons to the 2p orbitals of F atoms, and thus form strong Li-F ionic bonds. The IR, Raman and UV–Vis spectra are also acquired. Both the electrostatic potential and the dual descriptor suggest that the locations of Li and F atoms are the optimal reaction sites. [ABSTRACT FROM AUTHOR]