氮分子A^(3)Σ_(u)^(+)、B^(3)П_(g)、C^(3)П_(u)电子态的高温高振转光谱研究

Study on high temperature and high ro-vibrational spectra of A^(3)Σ_(u)^(+)、B^(3)П_(g)、C^(3)П_(u)electronic states of nitrogen molecules

采用态平均(CASSCF)/高度相关多参考组(MRCI)方法,对N_(2)分子A^(3)Σ_(u)^(+)、B^(3)П_(g)、C^(3)П_(u)电子态的势能、跃迁偶极矩进行了高度相关的精确计算.计算的势能在平衡位置附近与RKR拟合的势能曲线非常一致,获得的跃迁偶极矩与已有实验值符合很好.首次对A^(3)Σ_(u)^(+)、B^(3)П_(g)、C^(3)П_(u)电子态的振转光谱常数随振动量子数v的变化进行系统定量计算,其结果与已有的实验观测数据相符.同时,获得了N_(2)分子第一正带系的0-1、0-2、1-0、1-2、1-3、2-0、2-1、2-3、3-0、3-1和3-2光谱带分别在300,3000,6000,10000 K时的谱线强度,如1-0带在3000,6000,10000 K时的高温谱线带强度分别为1.58543×10^(-16) cm^(-1)/(分子cm^(-2))、6.07889×10^(-17) cm^(-1)/(分子cm^(-2))和2.3781×10^(-17) cm^(-1)/(分子cm^(-2)).这些结果对N_(2)分子进一步的理论研究、实际应用和高温大气的建模与研究具都有一定的参考价值.

The state-averaged complete active space self-consistent field(CASSCF)and the multi-reference configuration interaction(MRCI)approaches were employed to calculate the potential energies(PEs)and electronic transition dipole moments(TDMs)of the A^(3)Σ_(u)^(+),B^(3)П_(g) and C^(3)П_(u) states of N_(2).The calculated potential energy near the equilibrium position is very consistent with the potential energy curve fitted by RKR,and the transition dipole moments obtained are in good agreement with the existing experimental values.For the first time,the ro-vibrational spectral constants of A^(3)Σ_(u)^(+)、B^(3)П_(g)、C^(3)П_(u) electronic states with the variation of vibrational quantum number v are calculated systematically and quantitatively.The results are consistent with the existing experimental data.At the same time,the spectral line intensities of 0-1,0-2,1-0,1-2,1-3,2-0,2-1,2-3,3-0,3-1 and 3-2 bands of the first positive band system of N_(2) molecule were obtained at 300,3000,6000 and 10000 K,respectively.For example,high temperature band intensities of 1-0 band at 3000 K,6000 K and 10000 K were 1.58543×10^(-16) cm^(-1)/(molecular cm^(-2)),6.07889×10^(-17) cm^(-1)/(molecular cm^(-2))and 2.3781×10^(-17) cm^(-1)/(molecular cm^(-2)),respectively.These results are valuable for further theoretical study,practical application,modeling and research of high temperature atmosphere.