H_2S里德堡序列共振增强多光子离化光谱

Resonance Enhanced Multiphoton Ionization Spectrum of H_2S Molecular Rydberg Series

以纳秒Nd：YAG脉冲激光器三倍频（355nm）激光抽运的染料激光器为激发光源，在484～520nm波长范围内，采用共振增强多光子离化光谱（REMPI）方法，对HzS分子里德堡序列的能级特性进行了实验研究，得到了谱峰间隔随激光波长增长而呈近二倍变化的两套谱峰序列嵌套而成的规则序列。该谱峰序列对应于H2S分子的里德堡序列激发。依据H2S分子低位激发电子态及里德堡序列的势能高度，可将离化过程确定为五光子4＋1离化过程。并将所得到强谱峰序列归属为集结于H态的np（n=5，6，7，8）里德堡序列，将弱谱峰序列归属为集结于D态的ns（n=6，7，8）里德堡序列。两套序列的量子亏损分别为δ1=0．92和δ2=1．52。所得结果对H2S分子的光学检测及光谱特性研究具有重要意义。

The level characteristics of H2 S molecular Rydberg series have been studied with the method of resonance enhanced multiphoton ionization spectroscopy （REMPI） in the range of 484-520 nm, in which the third harmonic output （355 nm） of a nanosecond pulsed Nd： YAG laser excited dye laser is used as excitation source. The result is that regular series include two sets of spectral peak series nested in the way that the spectral peak interval appears twice changes with the increase of the wavelength. It is clear that this spectral peak series corresponds to the Rydberg series. Based on low-lying excited electronic states and potential height Rydberg sequence, this ionization process has been confirmed five photons ionization （four and one）. Now the strong spectral peak series has been assigned to the H2 S molecule in concentrating to H state n p （n = 5, 6, 7, 8） Rydberg series, and the weak spectral peak series has been assigned to the H2S molecule in concentrating to D state ns （n = 6, 7, 8） Rydberg series. Quantum losses of the two sequences are δ1 = 0.92 and δ2 = 1.52. The results are important to study the optical detection and spectroscopy characteristics of H2S molecules.