- The typical method of expressing wavelength of radiation is by expressing it as a unit of length like m or nm. Reporting wavelength in units of wavenumbers only occurs in the near infrared and infrared region of the electromagnetic spectrum. It is a measure of length but not in the same format you are used to seeing it. The conversion to other more traditional units of measurement is not complicated but does require your understanding of the relative sizes of the units used.
- In the infrared and near infrared region, wavelengths on the scale of microns are typical. Converting from wavenumbers to microns is accomplished by utilizing a conversion factor that changes cm^-1 to microns. There are 10,000 microns per cm. To convert wavenumbers to microns, divide 10,000 by the number of wavenumbers to yield the wavelength expressed in microns.
- The closest wavelength range to the near infrared is the visible spectrum. The human eye can see these wavelengths. Everything that you perceive every day emits or reflects light in the range of approximately 400 to about 700 nm. The conversion of wavenumbers to nm is possible by using a conversion factor of 10,000,000 nm per cm. Divide 10,000,000 by the number of wavenumbers to yield the wavelength in units of nm.
- You can convert wavenumbers to any other unit of measurement for wavelength in other regions of the electromagnetic spectrum. The limitation you will reach is that you must understand the relative size of each of the other units of measure to cm. The conversion factor incorporates the relative size difference of the unit of measure to cm. Divide the relative difference by the wavenumbers. The result of this calculation is the wavelength in the new unit of measure.
Wavenumbers are Wavelengths
Wavenumber to Microns
Wavenumbers to Nanometers
Conversion to Other Spectral Regions
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