主题：请教红外常用波数(cm-1)与波长之间的转换关系，好象很简单似的...，但...

怎么没人回答啊！

波数就是波长的倒数。红外好像不用抽真空吧，我没听说过要抽真空。

波数: 每cm中波的个数

红外分析气体之前我们要求要抽真空的（虽然我觉得那个真空泵很差...）

大家再请看下面的内容，我提此问题来源于此：

Wavelength calculation

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In the original data files from Kurucz only one wavelength value is listed for each line. For wavelengths below 200 nm this is the vacuum wavelength of that line; for those above 200 nm, it is the air wavelength, calculated from Edlen's formula (B. Edlen, Metrologia Vol. 2, 71 (1966)). (I'm not perfectly sure about this last point, that means with which formula Bob Kurucz calculated the air wavelengths.)
In this version of the spectral line database, searching for wavelengths is done on Kurucz' original data. That means, for wavelengths below 200 nm, the search is done for vacuum wavelength; for wavelengths above 200 nm, the search is done on air wavelengths.
In the one-column wavelength output, wavelengths are given as they appear in the original Kurucz data files, that is, vacuum wavelength below 200 nm and air wavelength above 200 nm.
In the two-column wavelength output from this search program, for wavelengths between (currently) 185 nm and 200 nm the air wavelength is calculated from the given vacuum wavelength using Edlen's formula.
Above 200 nm, in the two-column wavelength output the vacuum wavelength for a line is calculated by applying Edlen's formula to the air wavelength given in the data. However, because in this approach I had to insert the air wavelength into the dispersion formula instead of the vacuum wavelength, as it would be correct, in some lines with wavelengths above 200 nm a round-off error in the last digit of the vacuum wavelength value might appear.

对的

原文由 zhaim(zhaim) 发表:
我们均知：红外常用波数(cm-1)来作为单位，UV-VIS常用波长nm做单位。

波数一般又有“真空”与“大气”中波数之分，但一般用红外仪器测量时均不特别说明是在真空还是大气中的波数，当然，这本身是有点不科学。

有以下问题想请教大家：
1、我们一般用红外仪器所测的波长单位(cm-1)是为真空还是大气中的呢？如何界定？是指吸收池先抽了真空还是其它什么呢？

2、为了有一个恒定的比例因子，即均用真空的波数来比较，那么我们UV-VIS仪器空气中用nm单位的如何换算成真空下用波数(cm-1)的单位？
  (注：应该不是直接取倒数的关系，即1nm=10e+7/(cm-1)是不正确的，)

要是严格的计算，还是查表吧：

《波数表、空气中的波长：真空中的波数换算表 波长范围2000-10000》

【作　者】：凯塞尔，H.著；张佩环译

【装帧项】：26cm / 106页

【出版项】：科学出版社 / 1964

【ISBN号】：无

【原书定价】：￥1.50

【主题词】：光度学

1.200nm的紫外区和红外有很大的区分。一般而言，200nm以下必须在真空里面测，空气里面你基本是无法测量的。红外则不然。
2.真空和空气中，对于标准片之类的，确实测量结果会有细微差异，比如0.001波数。但对于绝大部分仪器的精度而言，完全忽略不计。

如果你需要做超高分辨的精细光谱，你需要考虑。否则，没有任何考虑的必要。