Rb_2分子激发态与基态原子碰撞能量转移  

Collisional Energy Transfer for Rb_2 in Excited State by Rb Atoms

作　　者：李鹏[1] 王雪燕[1] 周冬冬[1] 王倩[1] 戴康[1] 沈异凡[1] 

机构地区：[1]新疆大学物理科学与技术学院,新疆乌鲁木齐830046

出　　处：《新疆大学学报（自然科学版）》2010年第4期465-468,共4页Journal of Xinjiang University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(10664003)

摘　　要：脉冲激光667nm线激发Rb2基态到低激发态B1Πu态,研究Rb2(B1Πu)+Rb→Rb2(X1Σ+g)+Rb(5PJ)的碰撞转移过程.测量不同Rb密度下B1Πu的时间分辨荧光强度,它是一指数衰减函数,取其光强对数描绘得到B1Πu的有效寿命τ3为23.5ns(温度为545K时的寿命).从描绘出的有效寿命倒数与Rb原子的粒子数密度的关系直线的斜率得出B1Πu态总的碰撞猝灭截面为σ3=(4.33±0.14)×10-15cm2.测量Rb2的B1Πu→X1Σ+g在不同Rb密度下的时间分辨和时间积分荧光强度,得到Rb2(B1Πu)+Rb→Rb2(X1Σ+g)+Rb(5P1/2)的碰撞截面σ31=(2.86±0.13)×10-16cm2,Rb2(B1Πu)+Rb→Rb2(X1Σ+g)+Rb(5P3/2)的碰撞截面为σ32=(8.30±0.38)×10-16cm2.At different Rb densities, Rb vapor was irradiated in a glass fluorescence cell with pulses of radiation from a pumped -laser, populating Rb2（B^1∏u）state by single-photon absorption. Energy transfer in Rb2（B^1∏u） ＋ Rb（5S） collision is studied using methods of atomic and molecular fluorescence. The decay signal of time-resolved fluorescence from B^1∏u → X^1∑g^＋ transition was monitored. The effective lifetimes of the B^1∏u state can be resolved. The plot of reciprocal of effective lifetimes of the B^1∏u state against Rb densities yielded the slope that indicated the total cross section for deactivation and the intercept that provided the radiative lifetime of the state. The radiative lifetime 23.5ns for the B^1∏u is obtained. The cross section for deactivation of the Rb2（B^1∏u） molecules by collisions with Rb atoms is a3=（4.33 ± 0.14） ×10^-15cm^2. At the different Rb densities, the time-integrated intensities of the resulting Rb emission lines. I（5P3/2 ± 5S1/2） and I（5P1/2 → 5S1/2） were measured. The absolute values for Rb2（BIII~）TRb--~ Rb2（llE＋） ＋Rb（5Pj） collisional transfer cross sections have been obtained. The cross sections are a31 = （2.86 ±0.13） × 10^-16cm^2 （for transferring to 5P1/2） and a32= （8.30 ±0.38） × 10^-16cm^2（for transferring to 5P3/2 ）, respectively.

关 键 词：时间分辨荧光强度 碰撞能量转移 碰撞截面 碰撞猝灭 Rb2 

分 类 号：O562.3[理学—原子与分子物理]