Cs(7D_J)+Cs(6S_(1/2))间的碰撞能量转移

Energy transfer in Cs(7D_J)+Cs(6S_(1/2)) collisions

脉冲激光双光子激发Cs(6S1/2)到Cs(7DJ)态,在样品池条件下,利用原子荧光光谱方法研究了Cs(7DJ)+Cs(6S1/2)的碰撞能量转移过程。利用三能级模型的速率方程分析,在不同的Cs(6S 1/2)密度下,通过对直接荧光和转移荧光的时间积分荧光强度测量,得到了7D5/2→7D3/2精细结构转移截面为σ=(2.9±0.7)×10-14cm2。而碰撞转移到7DJ以外的猝灭截面分别为(7.4±2.1)×10-14cm2(对J=5/2)和(6.6±1.8)×10-14cm2(对J=3/2)。结合已有的实验结果,得到7DJ转移到8P态的截面分别为(0.6±0.3)×10-14cm2(对J=5/2)与(0.8±0.4)×10-14cm2(对J=3/2)。7DJ态主要是通过碰撞能量合并的逆过程〔即7DJ+6S→5D+6P〕猝灭。

Cs vapor in a glass cell was irradiated with pulses of radiation from a YAG- laser- pumped OPO laser, populating 7Dj state by two- photon absorption. Energy transfer in 7Dj ＋ 6S1/2 collision is studied using methods of atomic fluorescenee. The resulting fluorescence included a direct component arising from the decay of the optically excited and a sensitized component arising from the collisionally populated state. At the different densities, we have measured the time - integrated intensities of the components and fitted a three-state rate equation model to obtain the cross section σ=（2.9±0.7）×10^-14cm^2 for 7D5/2→7D3/2 tramper. The cross section for excitation transfer out of the 7Dj doublet are （7.4±2.1）×10^-14cm^2 （for J = 5/2 ） and （ 6.6±1.8）×10^-14 cm^2 （ for J = 3/ 2 ）, respectively. A comparison with previous results yields that the cross sections for 7Dj→8P transfer are （0.6±0.3）×10^-14 cm^2（ for J = 5/2 }and （0.8 ± 0.4） ×10^-14 cm^2 （ for J = 3/2 ）, respectively. The 7Dj state is quenched mainly in the reverse energy polling processes [ i.e., 7Dj ＋ 6S→5 D ＋ 6P].