Rb_2（~1Λ_g）高位态的预解离和碰撞转移过程

Predissociation and collisional transfer on the high-lying on the Rb_2（~1Λ_g）

池温控制在519-548K之间,在不充任何缓冲气体的纯Rb样品池中,Rb原子密度在4-8×1015cm-3范围,Rb2分子的粒子数密度数量级为1014,利用YAG脉冲激光器的680nm激光双光子激发Rb2的X1Σg+态至1Λg高位态.利用激光感生荧光光谱法研究Rb2(1Λg)+Rb(5S)→Rb(6 D,8S)的预解离和碰撞转移.在不同的Rb原子密度下探测1Λg→B1Πu的时间分辨荧光,得到不同Rb密度N时1Λg态的有效寿命.利用Stern-Volmer方程,看出有效寿命的倒数与Rb密度成线性关系,从直线的截距和斜率分别得到1Λg→B1Πu辐射寿命与预解离率之和及总的碰撞截面.用光子计数器测量时间积分荧光强度I3[Rb2(1Λg→B1Πu)],I2[Rb(8S→5P3/2)]和I1[Rb(6 D→5P3/2)],从直线的斜率和截距并结合从Stern-Volmer方程得到的结果,确定Rb2(1Λg)的预解离率,ΓP8S=(6.5±0.6)×106 S-1,ΓP6 D=(4.1±0.3)×106 S-1和碰撞转移截面σ8S=(7.9±0.7)×10-13cm2,σ6 D=(6.2±0.3)×10-13cm2.

Using a YAG-laser pumped OPO laser excite the pure rubidium cell,the Rb2（1Σg） state was excited to Rb2（1Λg） state,the temperature controlled between 519-548K while Rb atomic density ranged 4-8×1015cm-3 and Rb2 density was about 1014cm-3.The fluorescence spectrum of cesium vapor was used to study predissociation and transfer collision.From time-resolved fluorescence for the 1Λg →B1Πu transition at different Rb densities,the effective lifetimes of the 1Λg state could obtain.Based on the Stern-Volmer equation,the sum of the radiative and predissociative rates and the total cross section for deactivation of the Rb2（1Λg） were from the slope and the intercept,due to a linear relationship between the effective lifetime reciprocals and Rb densities.The time-integrated intensities of I3[Rb2（1Λg→B1Πu）],I2[Rb（8S→5P3/2）]and I1[Rb（6D→5P3/2）] were measured by photon counter.By combining the slope and the intercept with the result obtained by the Stern-Volmer equation,we obtain predissociative rates ΓP8S=（6.5±0.6）×106S-1,ΓP6D=（4.1±0.3）×106S-1,and collisional transfer cross sections σ8S=（7.9±0.7）×1013cm2,σ6D=（6.2±0.3）×10-13cm2.