GEOMAR  Research  Marine Biogeochemistry  Marine Geosystems  Benthic Biogeochemistry  Gas hydrate technologies  Raman spectroscopy

Raman spectroscopy

Raman spectroscopy is a non-destructive and non-invasive technique to extract chemical and physical information about solid, liquid, gaseous and dissolved compounds. In the Raman experiment a beam of monochromatic light, usually from a laser, is focused onto a sample. Interaction of the light with the electronic environment of the molecules leads to elastic (Rayleigh) and inelastic (Stokes/Anti-Stokes) scattering of the incident photons. The Stokes bands carry the signature of the vibrational modes of the molecules in the excited sample volume, which are used to identify the composition, physical state, and concentration of compounds in the sample. 

Equipment 

A. Raman microscope LabRAM HR800 from Horiba Jobin Yvon
* Nd-YAG laser (532 nm, 50 mW)
* gratings of 600 and 1800 /mm
* multi-channel CCD detector (1024 x 256  pixel per 26 x 26 µm2)
* high spectral resolution of max. 0.5 cm-1
* focal length of 800 mm
* objectives: 10x, 50x, 100x, 50x (long working distance)
* motorized working table for mapping of samples in XYZ-direction in <1 μm steps
* working table with shock absorption (90% dampening for vibrations >8 Hz)

B. Raman spectrometer iHR SP320-U from Horiba Jobin Yvon
* Nd-YAG laser (532 nm, 500 mW)
* gratings of 600 and 1800 /mm
* multi-channel CCD detector (1024 x 256  pixel per 26 x 26 µm2)
* high spectral resolution of max. 1 cm-1
* focal length of 320 mm
* objectives: macro lens
* Multiplexing for simultaneous measurement at 4 different spots
* 4 SuperHead sensors with fibre optic cables for remote analyses in high-pressure cells

Applications

* Gas hydrates: Identification of the composition and structure of gas hydrates as well as determination of their formation, dissociation, and conversion kinetics. The Raman signals provide precise information about the type of guest molecule amd its cage occupancy. It offers a means to distinguish between the hydrate phase, the gas/liquid phase, and the dissolved phase. It is, therefore, ideally suited to study guest-host interactions, phase transitions and mass transfer between phases as well as spatial heterogeneities of those parameters within the sample. We also attempt to quantify the Raman signal to determine solute concentrations.

* Investigation of natural minerals: microbially-mediated formation of authigenic carbonates, identification of carbonates, sulphates, silicates, and fluid inclusions in rocks

LabRAM HR800 spectrometer.
LabRAM HR800 spectrometer.
High-pressure Raman cell placed on the motorized microscope stage. The laser beam is focused through a quartz glass window into the cell to determine CH4 and CO2 in all phases (gas, liquid, dissolved, gas hydrate) and resolved in space and time.
High-pressure Raman cell placed on the motorized microscope stage. The laser beam is focused through a quartz glass window into the cell to determine CH4 and CO2 in all phases (gas, liquid, dissolved, gas hydrate) and resolved in space and time.
iHR SP320-U Raman spectrometer for measuring dissolved gases and solutes in the fluid pumped through the NESSI reactor.
iHR SP320-U Raman spectrometer for measuring dissolved gases and solutes in the fluid pumped through the NESSI reactor.
SuperHead mounted to a high-pressure flow-through cell in the pipes entering & leaving the sample reactor of NESSI.
SuperHead mounted to a high-pressure flow-through cell in the pipes entering & leaving the sample reactor of NESSI.
RD2
Marine Biogeochemistry

Contact

  • Dr. rer. nat. Matthias Haeckel
    Room: 8/D-128
    Phone: +49 431 600-2123
    E-Mail: mhaeckel(at)geomar.de
    Address: Wischhofstraße 1-3; D-24148 Kiel

    Dr. Nikolaus Bigalke (Raman)
    Room: 12-202
    Phone: +49 431 600-1410
    E-Mail: nbigalke(at)geomar.de
    Address: Wischhofstraße 1-3; D-24148 Kiel

    Christine Utecht - Assistant
    Room: 8-D 103
    Phone: +49 431 600-2116
    E-Mail: cutecht(at)geomar.de
    Address: Wischhofstrasse 1-3; D-24148 Kiel

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