What is CM-1 in IR?

What is CM-1 in IR?

The wavelengths of infrared radiation are between 0.8 and 250 μm. The units that are typically used for infrared spectroscopy are wavenumbers (which is cm-1). IR spectroscopy analyzes radiation between 40 to 13,000 cm-1.

What is the FTIR range in cm-1?

4,000 to 400 cm-1
Fourier Transform Infrared spectrophotometers (FTIR) are mainly used to measure light absorption of so-called mid-infrared light, light in the wavenumber range of 4,000 to 400 cm-1 (wavelengths 2.5 to 25 µm), in order to identify and quantify various materials.

Why IR unit is CM-1?

Frequencies in IR are generally expressed in 1/ λ units; ie cm-1 since these are proportional to energy.

What is a cm-1?

A reciprocal centimeter (or wavenumber) is used as an energy unit. It is often used for the energy of vibrational levels and transitions, and for electronic energy levels and transitions. The spectra of vibrational and electronic transitions are often measured as an intensity as a function of wavelength.

What is the region of an IR below 1000 cm-1 called?

the fingerprint region
As an example, the IR spectrum of butanal is shown below. In general terms it is convienient to split an IR spectrum into two approximate regions: 4000-1000 cm-1 known as the functional group region, and. < 1000 cm-1 known as the fingerprint region.

What is a CM-1?

Why does IR use wavenumbers?

where n is the refractive index of the medium. Wavenumber is directly proportional to energy, so higher wavenumbers correspond to a higher energy by the same factor.

Does cm mean cm?

centimeter
The centimeter (abbreviation, cm) is a unit of displacement (distance or length) in the cgs (centimeter/gram/second) system of units. The cm is equivalent to 0.01 meter, and there are about 2.54 centimeters in one linear inch.

Can cm-1 have energy?

For example, the reciprocal centimetre, cm−1, is an energy unit equal to the energy of a photon with a wavelength of 1 cm. That energy amounts to approximately 1.24×10−4 eV or 1.986×10−23 J.