我们也知道振动能的配分函数。

We also know what the vibrational partition function is.

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都有对应的配分函数，每个自由度。

Then you can have a partition function for each of these degrees of freedom.

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对单个分子的配分函数本身也适用。

You can also look at the molecular partition function itself.

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现在我们来计算分子的配分函数。

So now let's figure out our molecular partition function.

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配分函数是什么,这些构型的？

so what's our molecular partition function for this configurational degree of freedom?

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这里分子的配分函数用q标记。

So the molecular partition function is labeled little q.

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我们总是写下，一些分子的配分函数。

So we're always writing some molecular partition function.

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我们写过了平动的配分函数。

So so far, we've written for translation partition function.

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总配分函数,是这两者之积。

Q And now the total system partition function is the multiplication of these two.

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现在qi是分子总配分函数。

Now, qi is just the total molecular partition function.

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系统的配分函数用Q标记。

And the system partition function is labeled big Q.

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能量相加，配分函数相乘。

If the energies add, then the partition functions multiply each other.

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好，这就是分子配分函数。

OK. So this is your molecular partition function.

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所以振动配分函数,等于。

So all the partition functions for the vibrations 1 are equal to one.

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这个求和叫做配分函数。

Just these sums, what are called partition functions.

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接着我们计算配分函数。

And we're going to calculate partition functions.

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要把配分函数分解成，子系统的配分函数。

So it's the separation of the partition functions into subsystem partition functions.

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我们可以把配分函数写成，对能级的求和。

We can write the partition function as a sum over energy level.

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这是电子的配分函数。

This is the electronic partition function.

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所以振动配分函数也没有什么变化。

So then nothing is going to change in the vibrations.

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我们的分子配分函数。

Our molecular partition function.

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在构型配分函数中。

In the configurational partition function.

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称为正则配分函数。

It's called the canonical partition function.

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现在我们有我们的大，我们的正则构型配分函数。

Q And now we have our capital Q, our canonical configurational partition function.

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不同自由度的能量要相加，相应的配分函数要相乘。

And whereas the energies of the degrees of freedom add up, the partition functions get multiplied.

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我们用的4种分子的振动配分函数都是。

For all four of the molecules.

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这意味着，配分函数，是带波耳兹曼常数的各项之和。

And what that means is, in the partition function, which is a sum over all these terms with these Boltzmann factors.

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而不是分子配分函数。

Not just the molecular one.

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同样的，对构型部分,也是分子构型配分函数的N次方。

You also have the system partition function for the configurations.

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上节课我们看到了如何,从正则配分函数导出，内能等量。

So last time, then, you saw how from the canonical partition function, you could get something like the energy.

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