Rb(5D-7S)-He,Ar,H_2的碰撞能量转移

Excitation Transfer in Rb(5D-7S)-He,Ar,H_2 Collisions

在样品池条件下,利用原子荧光光谱方法,测量了Rb(5D)-He,Ar,H_2碰撞中5D→7S的激发能量转移截面。获得的荧光包括由激发态产生的直接荧光部分和由于碰撞布居态而产生的敏化荧光部分。在不同的猝灭气体压强下,测量丁相关的两部分荧光的相对荧光强度,得到了Rb(5D)与He,Ar和H_2碰撞的5D→7S转移截面分别为(1.2±0.3)×10^(-17)cm^2,(1.3±0.3)×10^(-18)cm^2和(8.3±2.1)×10^(-17)cm^2。同时确定了Rb(7S)与He,Ar和H_2的碰撞猝灭速率系数。7S态与H_2的碰撞猝灭速率系数1.7×10^(-10)cm^3·s^(-1)比Rb(7S)与He,Ar的大得多,它是反应与非反应速率系数之和,利用实验数据确定Rb(75)与H_2的反应截面为(1.0±0.4)×10^(-16)cm^2,Rb(5D)与H_2反应截面为(7.1±2.9)×10^(-17)cm~。Rb(7S)与H_2的反应活动性大于Rb(5D)。

Cross sections for 5D→7S transfer in Rb, induced by collisions with He, Ar atoms, and H2 molecules, respectively, are determined by using methods of atomic fluorescence in a glass fluorescence cell. The resulting fluorescence includes a direct component arising from the optically excited state and a sensitized component due to the collisionally populated state. Measurement of relative intensities of the two components in relation with different quenching gas pressures yieldes the cross sections of σ（5D-7S） of （1.2±0.3） × 10^-17 cm^2, （1.3±0. 3）× 10^-18 cm^2 , and （8.3±2.1） × 10^-17cm^2 for He, Ar, and H2, respectively. Cross sections for the effective quenching of the 7S state are also determined. The total quenching rate coefficient out of the 7S state is much larger for H2 （1.7×10^-10cm^3.s^-1） than for He and Ar. And the coefficient corresponds to the reaction and nonreactive energy transfer. We detenmine the cross section of （1.0±0.4）× 10^-16cm^2 for reaction of Rb （7S） with H2 by experiment. And the cross section of （7.1±2.9）× 10^-17cm^2 for reaction of Rb （5D） with H2 is obtained. The relative reactivity with H2 is in an order of Rb （7S）〉Rb （5D）