Luo Wenlang

The geometry structures and electronic properties of LimBn (m + n = 12) clusters

The geometric structures, electronic properties, total and binding energies, harmonic frequencies, the highest occupied molecular orbital to the lowest unoccupied molecular orbital energy gaps, and the vertical ionization potential energies of small LimBn (m+n = 12) clusters were investigated by the density functional theory B3LYP with a 6-311+G (2d, 2p) basis set. All the calculations were performed using the Gaussian09 program. For the study of the LimBn clusters, the global minimum of the B12 cluster was chosen as the starting point and the boron atoms were gradually replaced by Li atoms. The results showed that as the number of Li atoms increased, the stability of the LimBn cluster decreased and the physical and chemical properties became more active. In addition, on average there was a large charge transfer from the Li atoms to the B atoms.

Na decorated B6 cluster and its hydrogen storage properties

The structures and hydrogen storage properties of sodium atoms decorated B6 clusters are investigated by the B3LYP method with a 6–311+G (d, p) basis set. For NamB6 (m = 1–3) clusters, Na atoms are always inclined to separate far enough from each other and not cluster together on a B6 cluster surface so that each Na atom has sufficient space to bind hydrogen molecules. The hydrogen storage gravimetric density of a two Na atoms decorated B6 cluster is 17.91 wt% with an adsorption energy per H2 molecule (AAE/H2) of 0.6851 kcalmol−1. The appropriate AAE/H2 and preferable gravimetric density of the two Na atoms decorated B6 cluster complex indicate that it is feasible for hydrogen storage application in ambient conditions.

Ground state for CH2 and symmetry for methane decomposition

Using the different level of methods B3P86, BLYP, B3PW91, HF, QCISD, CASSCF (4,4) and MP2 with the various basis functions 6-311G**, D95, cc-pVTZ and DGDZVP, the calculations of this paper confirm that the ground state is 3B1 with C2v group for CH2. Furthermore, the three kinds of theoretical methods, i.e. B3P86, CCSD(T, MP4) and G2 with the same basis set cc-pVTZ only are used to recalculate the zero-point energy revision which are modified by scaling factor 0.989 for the high level based on the virial theorem, and also with the correction for basis set superposition error. These results are also contrary to 3Σ−g for the ground state of CH2 in reference. Based on the atomic and molecular reaction statics, this paper proves that the decomposition type (1) i.e. CH4 → CH2+H2, is forbidden and the decomposition type (2) i.e. CH4 → CH3+H is allowed for CH4. This is similar to the decomposition of SiH4.