And so the energy is zero because the electron is no longer bound. It is free.

所以这个系统能量为0，因为,电子不再受束缚了，它自由了。

麻省理工公开课 - 固态化学导论课程节选

So, if we want to go from that stable state to that less stable state, we need to put in a certain amount of energy to our system, that difference between the free electron and the electron bound to the metal.

所以，如果我们想使电子,从稳态到达不够稳定的状态，我们需要引入一定数量的,能量到系统中，即自由电子和束缚于金属的,电子的能量差。

麻省理工公开课 - 化学原理课程节选

And how about potential energy? It is not bound.

那么什么是势能，答案不是一定的。

麻省理工公开课 - 固态化学导论课程节选

So we can think about what is our most loosely-bound electron, what's that highest energy orbital, and it's going to be the 2 p orbital, that's going to be what's highest in energy.

我们来想一想,它“束缚得最松“的电子是哪一个，能量最高的轨道是哪一个？,它就是，2，p，轨道，是能量最高的轨道。

麻省理工公开课 - 化学原理课程节选

So here we have energy increasing on the y-axis, and you see this straight line at the bottom here is lower down on the graph, and that's the energy of a bound electron, so that's going to be a low stable energy.

这里我们看到能量沿着y轴增加，而且在这张图片上,这条直线在底部是降低的，那是一个束缚电子的能量，所以那是一个低稳态能量。

麻省理工公开课 - 化学原理课程节选