N2第二正带系发射光谱的理论计算及实验研究

本文利用分子光谱理论系统的计算和分析N₂第二正带系(C³∏_u→B³∏_g)的发射光谱, 以研究光谱强度的分布规律与不同温度条件和气体条件的关系. 基于N₂的三重态能级结构特性, 重点计算和讨论了发射光谱的概个重要参数: 通过求解高、低电子态的哈密顿矩阵得到了振转能级特性; 利用r质心近似法求取了能级间跃迁的电偶极矩函数和爱因斯坦跃迁概率; 进而计算了不同振动和转动温度条件下谱线的强度分布. 进行了N₂和Ar的混合放电实验, 利用实验光谱数据同理论结果进行拟合分析, 确定了N₂分子的振动温度和转动温度分别约为4300 K和800 K. 另外由于潘宁离化效应, N₂浓度减小时谱线强度呈现先增强后减弱的趋势. 实验结果很好的验证了N₂第二正带系光谱理论计算的正确性.

Theoretical and experimental study of emission spectrum of the second positive system of N2

The optical emission spectrum of the second positive system of N₂(C³∏_u→B³∏_g)isanalyzed and calculated based on the energy structure of nitrogen radical triplet system. Some key parameters of the equation for the radiative transition intensity are evaluated theoretically, including the potentials of the upper and lower states obtained from diagonalizing their Hamiltonian matrices, the electronic transition moments calculated by using r-centroid approximation, and the Einstein coefficients of different vib-rotational levels. For comparing with the theoretical spectrum, we achieve the measured results from corona discharge experiments of N² and Ar. By fitting the measured spectral intensities and the calculated ones, the vibrational and the rotational temperatures are determined approximately to be 4300 K and 800 K. The results also demonstrate that with the reduction of nitrogen concentration, the intensity of N² radiative state first increases and then decreases due to Penning excitation from argon metastable states. The experimental results verify the correctness of the theoretical calculations on the second positive system.