应用激光吸收和荧光方法

测量了Rb(5PJ)态与He原子碰撞的精细结构转移和碰撞猝灭截面.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激发态原子的密度及空间分布

由此计算了5PJ→5S的有效辐射率.在T=340K和He密度0.5×1017 关键词： 碰撞能量转移; 荧光; 截面; 铷; 氮气; Abstract： Applying the cw laser absorption and fluorescence method

the cross sections for the fine structure mixing and quenching of the Rb(5PJ) state

induced by collisions with He atoms have been measured

Rubidium atoms were optically excited to 5 P3/2states.The excited atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single mode laser beam

tuned to the 5PJ→ 7S1/2 transitions.Transmission factors were calculated for the 5PJ→ 5S transitions.The fluorescence intensity I795 of the sensitized 5P1/2→ 5S1/2emission was measured as a function of He density in the range 0.5×1017< N <4× 1017cm-3at constant temperature T = 340 K.It was found that the quantity N/ I795 exhibited a parabolic dependence on N

confirming that the quenching of the 5PJ states is due to collision with He atoms

not due to Rb ground state atoms.The coefficients of the second-order polynomial fitted through the measured date yielded the cross sectionsσ3/2→1/2=(1.84± 0.61)× 10-17cm2 andσD=(1.07± 0.30)× 10-17cm2 for the 5PJfine-structure mixing and quenching

respectively

due to collision with He atoms. KeyWords： collision energy transfer; fluorescence; cross sections; Rubidium atoms; He atoms;