Theoretical Study of 1+2+1 Double-Resonance Multiphoton Ionization Probability
ZHANG Gui-yin1, LI Meng-jun1, JIN Wei-jia2, ZHENG Hai-ming3
1. Department of Mathematics and Physics, North China Electric Power University, Baoding 071003, China 2. Department of Electrical Engineering, North China Electric Power University, Baoding 071003, China 3. Department of Mechanical Engineering, North China Electric Power University, Baoding 071003, China
Abstract：The technique of resonance enhanced multiphoton ionization (REMPI) spectroscopy has already become an important method for studying the energy level structure of atoms and molecules. Analytic expression of 1+2+1 double REMPI probability of four-level system has been deduced with the theory of rate equation. Based on the expression, the present paper simulated the variations of ionization probability versus laser intensity, laser pulse duration and collision relaxation rate. It was found that in the 1+2+1 ionization mechanism the ionization probability increases with laser intensity, until saturation phenomenon appears in one and two excitation steps. If laser intensity increases further, the ionization probability will oscillate around the saturation value, and the oscillation amplitude will increase with laser intensity. With regard to the influence of laser pulse duration and collision relaxation rate on the ionization probability, the results show that the ionization probability increases from zero to the saturation value 1 with the increase in laser pulse duration, while it decreases linearly with the increase in collision relaxation rate.
[1] YE Di-fa, LIU Jie(叶地发，刘 杰). Physics(物理), 2009, 38：908. [2] ZHANG Gui-yin, JIN Yi-dong(张贵银，靳一东). Acta Phys. Sinica(物理学报), 2008, 57: 132. [3] Zhang G，Jin Y. Chin. Opt. Lett., 2008, 6: 800. [4] Li H, Bai J. Acta Phys. Chem. Sinica, 1995, 11: 107. [5] Seiko N, Yoshihisa M, Tadashi S, et al. J. of Molecular Structure, 2005, 779: 68. [6] Philis J G. J. of Molecular Spectroscopy, 2005, 232: 26. [7] Peet V. Optics Communications, 2007, 276: 161. [8] Wu H C, Chen C C，Chen Y T. Spectrochimica Acta Part A, 2008, 69: 27. [9] Hiroko!T, Hiroki O, Osamu S, Analytica Chimica Acta, 2010, 682: 72. [10] Yu D, Dong C, Cheng M, et al. Journal of Molecular Spectroscopy, 2011, 265: 86. [11] Zierhut M, Dümmler S, Roth W, et al. Chimical Physics Letters, 2003, 381: 346. [12] Zhang G, Li M, Jin Y. Optics & Laser Technology, 2012, 44: 675. [13] LU Tong-xing, LU Yi-qun(陆同兴，路轶群). Ji Guang Guang Pu Ji shu Yuan Li Ji Ying Yong(激光光谱技术原理及应用). Hefei: University of Science and Technology of China Press(合肥：中国科学技术大学出版社)，2009. 297, 298, 280, 179, 192. [14] Parker D H，Ultrasensitive Laser Spectroscopy. New York: Academic Press，1983. 234. [15] ZHOU Bing-kun, GAO Yi-zhi, et al(周炳琨，高以智, 等). Principle of Laser(激光原理). Beijing: National Defense Industry Press(北京：国防工业出版社)，2002. 135. [16] ZHANG Lian-shui，WANG Jian，FENG Xiao-min，et al(张连水，王 健，冯晓敏, 等). Chin. J. of Quant. Electro.(量子电子学报), 2009, 26: 193.
