超高泵浦功率下的Xe(6p[1/2]0, 6p[3/2]2, 和6p[5/2]2)原子的能量转移过程

本文研究了Xe(6p1/2]₀, 6p3/2]₂, and 6p5/2]₂)原子在聚焦条件下的动力学过程. 激发能级的原子密度在聚焦条件下会显著地增加，因此两个高激发态原子之间的energy-pooling碰撞的概率也会增加. 这种energy-pooling碰撞主要有三种类型. 第一种类型为energy-pooling碰撞导致的电离. 一旦将激发激光聚焦，就可以从侧面的窗口观察到非常明显的电离现象，不论激发能级是6p1/2]₀、6p3/2]₂或6p5/2]₂能级. 这种电离的产生机理是energy-pooling电离或者一个Xe^*原子再吸收一个光子产生电离. 第二种类型为跨越较大能极差的energy-pooling碰撞. 当激发能级为6p1/2]₀能级的情况下，两个6p1/2]₀原子碰撞会产生一个5d3/2]₁原子和一个6s''1/2]₀原子. 第三种类型为跨越较小能级差的energy-pooling碰撞. 以5个二次产生的6p能级为上能级的荧光强度都变得更强，并且这些荧光的上升沿都变得更陡峭. 产生这些6p原子的主要机理是energy-pooling碰撞并非简单的碰撞弛豫. 基于理想气体原子之间的碰撞概率公式，推导出两个6p1/2]₀原子的energy-pooling碰撞速率为6.39x10⁸s^-1. 此外，6s原子在聚焦条件下的密度也会增加. 因此所有的荧光曲线会因为辐射俘获效应而出现非常严重的拖尾.

Energy-Transfer Processes of Xe(6p[1/2]0, 6p[3/2]2, and 6p[5/2]2) Atoms under the Condition of Ultrahigh Pumped Power

The kinetic processes of Xe(6p1/2]₀, 6p3/2]₂, and 6p5/2]₂) atoms under the focused condition were investigated. The atomic density of the laser prepared state significantly increases. Therefore, the probability of the energy-pooling between two high-lying atoms increases. There are three major types of the energy-pooling collisions. The first type is the energy-pooling ionization. Once the excitation laser is focused, the obvious ionization can be observed from the side window whenever the laser prepared state is 6p1/2]₀, 6p3/2]₂, or 6p5/2]₂ state. Ionization of Xe is attributed to the energy-pooling ionization or a Xe? atom reabsorbing another excitation photon. The second type is energy-pooling with big energy difference. When the 6p1/2]₀ state is the laser prepared state, the energy-pooling collision between two 6p1/2]₀ atoms can produce one 5d3/2]₁ atom and one 6s''1/2]₀ atom. The third type is energy-pooling with small energy difference. The intensities of fluorescence lines are much stronger that five secondary 6p states act as the upper states, and the rising edges of these fluorescence lines are much steeper. The primary mechanism of generating the secondary 6p atoms is energy-pooling collision instead of collision relaxation. Based on the collision probability, the rate of energy-pooling between two 6p1/2]₀ atoms is deduced (6.39x10⁸s^-1). In addition, the 6s atoms also increase under the focused condition. Therefore, all the fluorescence lines are serious trailing by radiation trapping.