# I Spectra Units cm^(-1)?

Tags:
1. Apr 19, 2016

### kq6up

I am seeing units for atomic/molecular spectra listed as $cm^{-1}$. Is this based on the wave number $k$ for $\Psi=Asin(kx-\phi)$?

Thanks,
KQ6UP

2. Apr 19, 2016

### Staff: Mentor

It is then inverse of the wavelength of the emitted/absorbed light. It is a leftover of the early days of spectroscopy, where this was something relatively easy to measure.

3. Apr 20, 2016

Thanks