So, if instead you put your particle somewhere down here on the electric field, or on the wave, the electric field will now be in the other direction so your particle will be pushed the other way.

还有方向，所以如果,你把粒子放在这下面，电场的方向相反,粒子会朝另一个方向运动。

麻省理工公开课 - 化学原理课程节选

Specifically, it's always the z that forms the sigma orbital, and the reason is at least at a minimum for this class we always define the internuclear axis as the z axis, so this is always the z axis, so it's always going to be the 2 p z's that are coming together head-on.

特别的，z总是形成sigma轨道，这是因为至少在这个课里面,我们总是定义核间轴为z轴，所以这总是z轴，所以2pz轨道总是,朝一个方向出现。

麻省理工公开课 - 化学原理课程节选