通过激发转移和碰撞能量合并研究Rb 5~2P精细结构混合

Fine-structure mixing in 52p Rb atoms studied through excitation transfer and energy-pooling collisions

利用单模半导体激光器激发Rb原子到5P3／2态,将Rb空心阴极灯发射的6D5／2→5P3／2的 629．8 nm线作为吸收线。测量5P3／2态原子密度,由测得的激发态原子密度结合荧光强度比,得到能量合并过 程Rb(5P3／2)+Rb(5P3／2)→Rb(5D)+Rb(5S)的碰撞截面为(5．0±1．9)×10-14cm2。利用荧光法测量了Rb52P 精细结构碰撞转移截面。直接荧光是由5P3／2态发射的,敏化荧光是由精细结构碰撞转移和碰撞能量合并产生 的。由相对荧光强度得到了转移截面σ(5P3／2→5P1／2)=(3．0±0．9)×10-15cm2。碰撞能量合并速率系数比精 细结构混合率大一个数量级,与其它实验结果进行了比较。

Rb atoms were excited to the 5P3/2 level using a single-mode laser diode. The 5P3/2 state atom density was measured bv the absorption of line from a Rb hollow-cathode lamp. The excited atom density is combined with measured fluorescence ratio to determine collisional cross section for the energy pooling process [i.e. Rb（5P3/2）＋Rb（5P3/2）→Rb（5D）＋Rb（5S）]. The cross section is （5.0＋1.9）×10^-14cm^2. Cross section for 5P3/2 →5P1/2 transfer in Rb, induced in collision with ground-state Rb atoms, has been determined using methods of atomic fluorescence. The resulting fluorescence included a direct component arising from the optically excited state and a sensitized component due to the collisionally populated fine-structure state and the energy-pooling collisions. Measurement of relative intensities of the two components yielded the following cross section： σ （5P3/2 →5P1/2）=（3.0＋0.9） ×10^-15cm^2. it is found that the rate for the energy pooling is an order of magnitude more efficient than 5P3/2→5P1/2 mixture. Comparisons of our result with other experiments have been made.