【摘要】 目的应用GAMESS[14]程序和新的多参考态组态相互作用(MRCISD)对S2O分子基态和与基态具有相同对称性及多重度的两个低激发态的离解进行研究。方法采用完全活性空间自洽场(CASSCF),沿着S-S伸缩振动坐标详细地解析基态X珘1A’和两个激发态C珘1A’和珟D1A’的离解以及C珘1A’预离解。结果采用不同的方法,珟D1A’态所获得的离解模式不同。对于非态平均的CASSCF方法,C珘1A’态与珟D1A’态的离解极限都为SO(1Δ)+S(1D)。对于态平均的完全活性空间自洽场(SA-CASSCF)方法,珟D1A’态离解极限与基态X珘1A’相同,均为SO(3Σ-)+S(3P),而C珘1A’态的离解极限为SO(1Δ)+S(1D)。X珘1A’态的离解能在MRCISD水平约为3.10 eV,比热化学值3.45±0.01 eV小0.35±0.01 eV。结论计算的C珘1A’态的预离解极限存在于S-S伸缩振动的26谱带附近,与实验值吻合得很好。更多还原

【Abstract】 Aim To analyze the dissociation and predissociation of the ground state and two low-lying excited states for the asymmetric sent S2O.Methods The complete active space self consistent field(CASSCF) method and multi-reference configuration interaction with single and double electron excitations have been employed to calculate the potentional energy curves(PECS) of three states.Results According to the calculations,the predissociation limit of 1A′ is found to be located in the vicinity of 26 or 25(reckoning in the zero-point energy revision) S-S stretching vibration level.Conclusion The dissociation of three states has been clarified by the CASSCF and MRCISD Methods.The predissociation limit of 1A′ state is in good agreement with the available experimental data.更多还原