Raman minerals
Raman shift[edit | edit source]
In colloquial usage, Raman shifts are typically in wavenumbers, which have units of inverse length. In order to convert between spectral wavelength and wavenumbers of shift in the Raman spectrum, the following formula can be used:
- <math>\Delta w = \left( \frac{1}{\lambda_0} - \frac{1}{\lambda_1} \right) \ , </math>
where <math>\Delta w</math> is the Raman shift expressed in wavenumber, λ<sub>0</sub> is the excitation wavelength, and λ<sub>1</sub> is the Raman spectrum wavelength. Most commonly, the units chosen for expressing wavenumber in Raman spectra is inverse centimeters (cm<sup>−1</sup>). Since wavelength is often expressed in units of nanometers (nm), the formula above can scale for this units conversion explicitly, giving
- <math>\Delta w (\text{cm}^{-1}) = \left( \frac{1}{\lambda_0 (\text{nm})} - \frac{1}{\lambda_1 (\text{nm})} \right) \times 10^{7}, \text{effectively multiplying by } \frac{(\text{nm})}{(\text{cm})} . </math>