Fourier Transform Infrared (FTIR) Spectrometer

GFZ - German Research Centre for Geosciences

last updated: July 19, 2023

About the Laboratory

Fourier Transform Infrared (FTIR) Spectrometer

GFZ - German Research Centre for Geosciences

@ Section 3.6 Chemistry and Physics of Earth Materials

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Description

In our lab we use a FTIR-spectrometer Vertex 80v manufactured by Bruker. It is equipped with various light sources, beam splitters and detectors to operate from 25.000 cm⁻¹ to 80 cm⁻¹. The maximum resolution is 0.25 cm⁻¹. An attached IR-microscope (Bruker Hyperion 2000) provides the possibility to perform unpolarized and polarized measurements on single crystals in the energy range of 25.000 cm⁻¹ to 420 cm⁻¹ with a spatial resolution of 20 µm.
Additional equipment: Heating/cooling stage Linkam THM600 (microscope) operable von -196 bis 600°C; Variable Temperature cell from -190 to 250°C (vaccum chamber); Megabar-type diamond-anvil cells (Mao & Hemley, 1998: Review in Mineralogy, 37); Internally heated diamond-anvil-cells (Diacell μScope von easylab) with gas membran for pressure generation.

Instruments

FTIR SPECTROMETER - Fourier Transform Infrared Spectrometer Traditional (dispersive) infrared techniques experience difficulties due to the '1 wavenumber at a time' nature of data acquisition. This leads to either a poor signal to noise ratio in a spectrum or a very long time needed to obtain a high quality spectrum. Both these situations cause problems with kinetic work. The first gives inherent large errors, the second prohibits in-situ work. These problems can be overcome using Fourier transform infrared spectroscopy (FT-IR) that is based on the interferometer originally designed by Michelson and a mathematical procedure developed by Fourier that converts response from the 'time' to the 'frequency' domain. In the Michelson interferometer a parallel, polychromatic beam of radiation from a source (A) is directed to a beam splitter (B), made from an infrared transparent material, such as KBr. The beam splitter reflects approximately half of the light to a mirror, known as the fixed mirror (C), which in turn reflects the light back to the beam splitter. The rest of the light passes through to a mirror, moving continuously, at a known velocity, back and forth along the direction of the incoming light and this is known as the moving mirror (D). Upon reflection from the moving mirror, radiation is then directed back to the beam splitter. At the beam splitter some of the light that has been reflected from the fixed mirror combines with light reflected from the moving mirror and is directed towards the sample. After passing through the sample (E) the radiation is focused onto the detector (F). The detectors are sufficiently fast to cope with time domain signal changes from the modulatio n in the interferometer. Additional information available at http://physics.nist.gov/Divisions/Div842/Gp1/fts_intro.html (Source: Global Change Master Directory (GCMD). 2023. GCMD Keywords, Version 16.3 [...] )
FTIR Spectrometer - Fourier Transform Infrared Spectrometer

Analytical Methods

FTIR SPECTROMETER - Fourier Transform Infrared Spectrometer Traditional (dispersive) infrared techniques experience difficulties due to the '1 wavenumber at a time' nature of data acquisition. This leads to either a poor signal to noise ratio in a spectrum or a very long time needed to obtain a high quality spectrum. Both these situations cause problems with kinetic work. The first gives inherent large errors, the second prohibits in-situ work. These problems can be overcome using Fourier transform infrared spectroscopy (FT-IR) that is based on the interferometer originally designed by Michelson and a mathematical procedure developed by Fourier that converts response from the 'time' to the 'frequency' domain. In the Michelson interferometer a parallel, polychromatic beam of radiation from a source (A) is directed to a beam splitter (B), made from an infrared transparent material, such as KBr. The beam splitter reflects approximately half of the light to a mirror, known as the fixed mirror (C), which in turn reflects the light back to the beam splitter. The rest of the light passes through to a mirror, moving continuously, at a known velocity, back and forth along the direction of the incoming light and this is known as the moving mirror (D). Upon reflection from the moving mirror, radiation is then directed back to the beam splitter. At the beam splitter some of the light that has been reflected from the fixed mirror combines with light reflected from the moving mirror and is directed towards the sample. After passing through the sample (E) the radiation is focused onto the detector (F). The detectors are sufficiently fast to cope with time domain signal changes from the modulatio n in the interferometer. Additional information available at http://physics.nist.gov/Divisions/Div842/Gp1/fts_intro.html
Infrared spectroscopy in which a Fourier-transform spectrometer is used to separate the transmitted radiation into its component wavenumbers. (Source: IUPAC; https://iupac.org/wp-content/uploads/2019/10/PAC-REC-19-02-03.R2_PR191002MC.pdf (Source: Global Change Master Directory (GCMD). 2023. GCMD Keywords, Version 16.3 [...] )
FTIR Spectroscopy - Fourier Transform Infrared Spectroscopy

Laboratory Keywords

Disciplines

Geoscience > Geochemistry > Geochemistry
Geochemistry
Geoscience > Geophysics > Mineral Physics
Mineral Physics

The Research Network for Geosciences in Berlin and Potsdam

Fourier Transform Infrared (FTIR) Spectrometer

GFZ - German Research Centre for Geosciences

About the Laboratory

Fourier Transform Infrared (FTIR) Spectrometer

Access

Description

Instruments

Analytical Methods

Laboratory Keywords

Disciplines

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