Multiple exciton generation (MEG) of Si₆X(X=Cu, Ag and Au) clusters is investigated by using symmetry adapted cluster theory with configuration interaction and pseudo potential LANL2DZ basis set. Before MEG calculations, geometrical structures of clusters are optimized and their energy stabilities are confirmed by frequency analysis based on density functional theory method and all-electron double zeta valence quality plus polarization functions primary basis sets DZP-DKH. It indicates that double exciton is found dominating component and MEG of clusters appear in visible range although the strong part is in ultraviolet light range, which provides information for potential materials utilizing MEG to harvest energy of solar light.

In a one-dimensional radiation transfer model, energy distribution and spectral absorption mechanism of greenhouse effect under Pre-Industrial and current atmospheric compositions were analyzed. Coupling mechanism between greenhouse effect and surface temperature was investigated on the basis of greenhouse gas concentrations at current level. It shows that warm environment before Industrial Revolution is mainly due to three strong absorption bands of greenhouse gases, which are (100-370)cm^-1, (640-710)cm^-1 and (1370-2000)cm^-1 respectively. However, current global warming is originated from weak absorption bands of greenhouse gases, that is, radiation absorptions by (370-640)cm^-1 and (710-1370)cm^-1. Contributions to greenhouse effect increment of these weak bands after Industrial Revolution are 25% and 55% respectively. With rising temperature, contribution of right side of the earth's radiation peak wavenumber to total greenhouse effect shows positive change, while contribution of left side shows negative change.