中文摘要：

本文探讨了快电子碰撞下判别原子跃迁多极性的方法，指出了从实验上由广义振子强度比和光学振子强度比及中间耦合系数的归一化特性来确定中间耦合系数的方法．然后以氩原子为例，计算了其价壳层激发的中间耦合系数，并在2500eV入射能量下实验测量了氩原子跃迁到3p^54s[3／2]1和3p^54s′[1／2]1的广义振子强度比，在此基础上阐明了氩原子价壳层激发的多极性，从实验上获得了氩原子3p^54s[3／2]1和3p^54s′[1／2]1的中间耦合系数．本文得出了LS耦合的波函数足以描述氩原子的光子或快带电粒子碰撞激发过程的结论，这是由于氩原子基态的LS耦合特性在快电子激发过程中选择了激发态波函数中的单态成份决定的．并指明该结论可以推广到描述其它原子的光子或快带电粒子的碰撞激发过程．

英文摘要：

In this work we propose the methods to judge the transition multipolarities of atoms, and we elucidate the methods to determine the intermediate coupling coefficients from the ratios of generalized oscillator strengths or optical oscillator strength and the normalization characteristic of the intermediate coupling coefficients. Then as an example, the intermediate coupling coefficients for the valence shell excitations of Ar have been calculated by Cowan Code, the generalized oscillator strength ratio between the valence excitations of 3p^54s[3/2]1 and 3p^54s′[1/2]1 of Ar have been measured at an incident electron energy of 2500 eV. Then the transition multipolarities for the valence shell excitations of Ar have been elucidated, the intermediate coupling coefficients of 3p^54 s [ 3/2 ] 1 and 3 p^54 s′ [ 1/2 ] 1 were determined experimentally. The conclusion that the wave functions of LS coupling are enough to describe the process of photo or fast electron excitation for Ar is obtained, the reason is the LS coupling singlet nature of the ground state of Ar selects the LS coupling singlet components from the intermediate coupling wave function of the excited state. It is pointed out that this conclusion can he extended to describe the processes of photo or fast electron excitation for other atoms.