类Li离子电偶极跃迁的碰撞强度

THE COLLISION STRENGTHS FOR THE DIPOLE TRANSITION OF Li-LIKE IONS

用半径经典方法计算类Ｌｉ离子电偶极跃迁的碰撞强度。用碰撞参数为ｂ的双曲线轨道描述入射电子的运动，用时间有关的微扰理论方法描述靶态的跃迁几率，通过对碰撞参数的积分求出电子碰撞激发截面。碰撞强度可表示成与振子强度成线性关系的简单公式。计算了若干个类Ｌｉ离子２ｓ－２ｐ１／２、２ｐ３／２的碰撞强度。结果表明，除在阈能附近以外，大部分数据与用较精确的相对论扭曲波的计算结果符合得很好。所用方法简单，而且可以进行快速计算。

In this paper, the collision strengths for dipole transition of Li-like ions are calculated by the semiclassical method. The trajectory of the incident electron is described by a hyperbolic orbit with impact parameter b . Probability of transition of the target ions is obtained by time-dependent perturbation theory. By integrating over the impact parameters, the cross sections and collision strengths are obtained. A simple formula for the collision strengths is expressed in terms of oscilation strengths. In this paper we have calculated the collision strengths of 2s-2p 1/2 , 2s-2p 3/2 transitions for some of the Li-like ions. It is shown that most of the results are in good agreement with those obtained from a sophistical calculation and the differences are within an uncertain of 15%. Because of its simplicity, it is useful in the practical use.