FTIR (Fourier Transform Infrared) spectroscopy is a technique used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas. It measures how much light is absorbed at each wavelength.
The formula to convert wavenumber to frequency is:
\[ f = \nu \times c \]
Where \( \nu \) is the wavenumber (cm⁻¹) and \( c \) is the speed of light (approximately \( 3 \times 10^{10} \) cm/s).
Consider a wavenumber of 1000 cm⁻¹:
Using the formula:
\[ f = 1000 \times 3 \times 10^{10} = 3 \times 10^{13} \, \text{Hz} \]
This means the frequency is \( 3 \times 10^{13} \) Hz.