Rb(5P)激发态的辐射及与N_2碰撞的能量转移  

Radiative transport and collisional transfer of excitation energy in Rb(5P)atoms mixed with N_2

作　　者：王青[1] 许瑾[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,乌鲁木齐830046

出　　处：《原子与分子物理学报》2008年第3期547-550,共4页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(10264004)

摘　　要：应用激光吸收和荧光方法,测量了Rb(5P)态与N2碰撞的精细结构混合和碰撞猝灭截面.Rb原子被激光激发到5P3/2态,将与泵浦激光束反向平行的检测激光束调到5PJ→7S1/2的跃迁,测量5PJ激发态的密度及空间分布,由此计算了5PJ→5S的有效辐射率.在T=340 K和N2密度0.5×1016<N<4×1016cm-3范围内测量了5P1/2→5S1/2(794 nm)发射的敏化荧光强度I794,量N/I794与N有抛物线型的关系,表明了5PJ的猝灭是由于与N2分子的碰撞产生的,而不是由与Rb基态原子碰撞产生的.由最小二乘法确定的二次多项式的系数得到5P态与N2碰撞精细结构混合截面σ3/2→1/2=(10.43±3.54)×10-16cm2,猝灭截面σD=(9.8±3.4)×10-16cm2.与在不同的实验条件下得到的结果在误差范围内一致.Applying the CW laser absorption and fluorescence method, the cross sections for the fine structure mixing and quenching of the Rb（5P）state, induced by collision with N2 molecules, have been measured. Cesium atoms were optically excited to the 5P3/2 state. The excited atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single mode laser beam, turned to the 5PJ→7S1/2 transitions. The effective radiative rates were calculated for the 5PJ→5S transitions. The fluorescence intensity I794 of the sensitized 5P1/2→5S1/2 emission was measured as a function of N2 density in the range 0.5 ×10^16〈 N〈 4 × 10^16cm^-3 at constant temperature T = 340 K. It was found that the quantity N/I794 exhibited a parabolic dependence on N, confirming that the quenching of the 5PJ states is due to collision with N2 molecules, not Rb ground state atoms. The coefficients of the second-order polynomial fitted through the measured data yielded the cross sections σ3/2→1/2 = （10.43 ± 3.54） × 10^-16cm^2 and σD = （9.8 ± 3.4） × 10^-16cm^2 for the 5PJ fine-structure mixing and quenching, respectively, due to collision with N2 atoms. Our values for these cross sections are in agreement, within combined error bars, with values we have recently obtained under different experimental conditions.

关 键 词：碰撞能量转移 荧光 截面 铷 氮气 

分 类 号：O562.5[理学—原子与分子物理]