单质分子和氮化物与卤化物，其核间距与力常数都表现有相似的行为。

The internuclear distances and force constants of the elementary molecules as well as of the nitrides and halides, exhibit a similar behavior.

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而我们就能更清楚地看到这些，如果我们画出，能量随核间距的变化曲线。

And we can actually better visualize this if we plot how that energy changes as a function of internuclear distance.

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因此，当我们考虑一个键的长度的时候，这就应该是我们的键长，这是合理的，因为体系会在核间距达到这一距离时，能量到达最小值。

So, when we think about a bond length, this is going to be the length of our bond here, that makes sense because it's going to want to be at that distance that minimizes the energy.

youdao

And we can actually better visualize this if we plot how that energy changes as a function of internuclear distance.

而我们就能更清楚地看到这些，如果我们画出,能量随核间距的变化曲线。

麻省理工公开课 - 化学原理课程节选

So, when we think about a bond length, this is going to be the length of our bond here, that makes sense because it's going to want to be at that distance that minimizes the energy.

因此，当我们考虑一个键的长度的时候，这就应该是我们的键长，这是合理的,因为体系会在核间距达到这一距离时,能量到达最小值。

麻省理工公开课 - 化学原理课程节选

So, if we look at this graph where what we're charting is the internuclear distance, so the distance between these two hydrogen atoms, as a function of energy, -- what we are going to see is a curve that looks like this -- this is the general curve that you'll see for any covalent bond, and we'll explain where that comes from in a minute.

因此，如果我们来看一看这幅曲线图,这里我们画的横坐标是核间距，也就是这两个氢原子之间的距离，纵坐标是能量，我们看到的这是能量关于核间距的曲线-,这是一条普遍的曲线，在研究任何共价键时你都会遇到，我们马上就会解释一下它是怎么来的。

麻省理工公开课 - 化学原理课程节选