K(4P_J)-N_2,He碰撞转移及猝灭截面的测量

Experimental Evaluation of the Cross-sectionsand the Quench-sections for the K(4P_J)-N_2,He

利用770nm脉冲激光激发基态K原子到K(4P1/2)态,在样品池中,利用原子荧光光谱方法,测量了K(4PJ)和N2、He碰撞的精细结构转移截面和碰撞猝灭截面。在不同N2、He气体密度下,通过对4P1/2→4S1/2共振荧光与4P3/2→4S1/2转移荧光的时间积分荧光强度进行测量,得到其荧光强度比与N2、He密度成线性关系。从荧光强度比R与(Nv)-1线性关系图中的直线斜率可以得到4P1/2→4P3/2转移截面为(2.77±0.69)×10-15cm2和4P3/2→4P1/2的碰撞转移截面为(1.62±0.41)×10-15cm2,从直线的截距计算出K(4P3/2)与N2、He的碰撞猝灭截面为(0.40±0.12)×10-15cm2和(0.60±0.18)×10-16cm2。

A K-N2（or He）mixture is irradiated in a fluorescence cell with pulses of 770nm radiation from OPO-YAG laser and populated K（4P1/2）state.Cross sections for K（4P1/2）→K（4P3/2）and quenching of the K（4P3/2）state is determined using the atomic fluorescence spectrometry.With the variable densities of N2（or He）,the intensities of time-integrated fluorescence from 4P1/2→4S1/2（the direct fluorescence）and 4P3/2→4S1/2（the transfer fluorescence）is measured.The ratio of the fluorescence intensity versus the densities of N2（or He）can be fitted by a straight line,the cross sections are（2.77±0.69）×10^-15cm^2 and（1.62±0.41）×10^-15cm^2 for K（4P1/2）→ K（4P3/2）by the slop,and the cross sections are（0.40±0.12）×10^-15cm^2 and（0.60±0.18）×10^-16cm^2 for the K（4PJ）quenching from the intercept.