作　　者： ; ; ; ; ;

机构地区： 河北大学物理科学与技术学院

出　　处： 《光学学报》 2004年第5期718-720,共3页

摘　　要： 以皮秒Nd∶YAG激光器抽运光学参变发生 /放大器做激发源 ,得到了NO分子在 4 90～ 5 80nm波长范围内通过C2 Π态共振增强的多光子离化谱 ,离化谱由有规则的谱线序列组成。将理论计算的峰值位置与实验结果进行比较 ,确定了离化通道为 :NO(X2 Π) 3hνNO(C2 Π) 2hν(orhν) NO+ +e ,离化信号强度随激光强度的近五次方变化关系进一步验证了此结论。分析讨论了谱线强度的分布不符合夫兰克康登原理的可能原因。根据谱线峰值位置 ,利用最小二乘法拟合获得NO分子C2 Π态振动常数′ωe=(2 35 4 .9± 6 .4 )cm-1,′ωe ′χe=(14 .7± 2 .5 )cm-1及平衡位置的力常数k=(2 .4 4± 0 .0 8)× 10 3 N·m-1。结果可为用激光离化光谱技术探测大气污染物NO分子提供参考。 Resonance enhanced multiphoton ionization (REMPI) spectrum of NO in the region of 490～580 nm is gained by using optical Parametric oscillator and Amplifier (OPO and OPA) as radiation source. The OPO/OPA is pumped by a Nd∶YAG laser. The spectrum is composed of regular band progressions. In comparision of the results of theoretical calculation with the experimental ones, the peaks of the spectrum are attributed to the C 2Π←X 2Π transitions. The ionization pathway can be shown as NO(X 2Π)hνNO(C 2Π)2hν (or hν)NO ++e. this conclusion is further verified with the near quintic variation of the ionization signal versus laser intensity. The possible reason that the distribution of the spectral intensity does not follow Franck-Condon principle is analyzed and discussed. The molecular constants about NO(C 2Π) state are calculated based on the experiment. The results are Yω′ e=(2354.9±6.4) cm -1 , Yω′ eYχ′ e=(14.7±2.5) cm -1 and force constant k=(2.44±0.08)×10 3 N·m -1 . The conclusion can provide reference for the detection of pollutant NO.

关 键 词： 分子光谱 分子物理学 一氧化氮分子 振动常量 多光子离化谱 谱线强度

领　　域： [理学] [理学]