This paper adopted the LANL2DZ pseudopotential basis set and B3LYP method to calculate the microstructure and electronic properties of HgmSen(m=1,2,3,n=1,2) molecules and molecular ion clusters. Meanwhile, it utilized the time-dependent density functional theory to calculate the absorption spectra, thus obtaining the ground state structure, electronic properties, binding energy, energy gap, dipole moments and other microscopic properties. Then it analyzed the frontier molecular orbital characteristics, identified all the harmonic vibration mode and absorption spectroscopic properties. The results show that: when m+n=1~3, the linear and angular types are the stable geometry with ground state; when m + n = 4 ~ 5, the ring type is the stable geometry with ground state, besides, compared with other molecular clusters, HgSe2 molecular cluster have the greatest stability, binding energy and the minimal energy gap. HgmSen(m=1,2,3,n=1,2) molecules and molecular ion clusters have better electron donors, receptors and other active sites, that is, great electrical conductivity. The maximum absorption wavelength λmax of each cluster with different composition lacks of regularity, but for the molecular clusters with the same composition and its corresponding positive and negative ions, there appears significant red shift or blue shift. The results could provide theoretical reference for the further experimental and applied research, and it is conducive to studying the nature of experiments as well as certain laws of massive condensed matter.
