What is wavenumber in FTIR?

A wavenumber is the reciprocal of a wavelength (1/λ); thus, a wavenumber of 1600 cm−1 corresponds to a wavelength of. 11600 cm−1=6.25×10−4cm or6.25 μ m. Organic chemists find it more convenient to deal with wavenumbers rather than wavelengths when discussing infrared spectra.

What is ATR mode in FTIR?

Attenuated total reflection (ATR) is a method that allows the direct measurement of samples for FTIR. ATR method involves pressing the sample against a high-refractive-index prism and measuring the infrared spectrum using infrared light that is totally internally reflected in the prism.

How do you compare spectra?

you can compare two spectra by means of the SAM (Spectral Angle Mapper), which actually consists on calculating the correlation coefficient between the two spectra….Dear Volker Linss,

1. The similarity of two spectra is equivalent to the similarity of two arrays of real.
2. Two different samples may have the identical spectra.

How do you calculate wavenumber?

The wave number for an EM field is equal to 2 pi divided by the wavelength in meters. (In some references, it is defined as the reciprocal of the wavelength in meters; in still others, it is defined as the reciprocal of the wavelength in centimeters.) As the wavelength grows shorter, the wave number becomes larger.

Why is wavenumber used in spectroscopy?

Wavenumber is unit of energy and therefore you can directly deduce the difference of energy between states. In addition, humans like to think in acceptably small numbers (0.01 – 10,000). Wavenumber allows this for IR and conveniently supplements the eV unit in small energy separations range.

How is ATR different from FTIR?

All Answers (15) FTIR is any Fourier Transform Infrared spectroscopy method in any measuring geometry, may it be transmission, reflection or whatever. ATR stands for attenuated total reflection and is developed in order to enhance the surface sensitivity since IR spectroscopy is a bulk method.