Yu Xiao-Guang

The analytical potential energy function of flue gas SO2(X1A1)

The equilibrium structure of flue gas SO2 is optimized using the density functional theory (DFT)/B3P86 method and CC-PV5Z basis. The result shows that it has a bent (C2V, X1A1) ground state structure with an angle of 119.1184°. The vibronic frequencies and the force constants are also calculated. Based on the principles of atomic and molecular reaction statics (AMRS), the possible electronic states and reasonable dissociation limits for the ground state of SO2 molecule are determined. The potential functions of SO and O2 are fitted by the modified Murrell—Sorbie+c6 (M-S+c6) potential function and the fitted parameters, the force constants and the spectroscopic constants are obtained, which are all close to the experimental values. The analytic potential energy function of the SO2 (X1A1) molecule is derived using the many-body expansion theory. The contour lines are constructed, which show the static properties of SO2 (X1A1), such as the equilibrium structure, the lowest energies, the most possible reaction channel, etc.

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.

Optical Transparency Induced by Periodic Modulation in a Passive Optical Coupler

We propose a scheme for the realization of optical transparency by using a periodically modulated optical coupler with losses in one waveguide. We discover that the increase of the transparency can be achieved only by varying the parameters of modulation, and such modulation-enhanced transmission is the consequence of phase transition of the quasi-energy spectrum. Our findings offer an efficient way to manipulate light transmission in realistic dissipative systems.

Enhancement of Localization in a Driven Four-Well System with Second-Order Coupling

We study theoretically the effect of second-order coupling (SOC) on the tunneling dynamics in a planar four-well system with only one well periodically modulated. We find that SOC between next-nearest neighboring wells facilitates localization. Due to SOC, the suppression of tunneling occurs over a finite range of parameters, in stark contrast to the normal coherent destruction of tunneling in the nearest-neighbor tight-binding approximation. This counter-intuitive phenomenon of SOC-enhanced localization can be attributed to the existence of a localized Floquet state rather than the degeneracy of quasi-energy levels in such a system.

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.