Raman spectroscopy and Infrared (IR) spec- troscopy are the two primary techniques to determine the vibrational modes of molecules. To a large extent these are complementary in that they measure two distinctly different physical phenomena. Infrared spectroscopy involves the measurement of absorption of light corresponding to transi- tions between the molecular energy levels of the vibration modes of molecules. In Raman Spectroscopy a monochro- matic visible light beam is scattered by the molecules. This scattered light is measured with a suitable spectrometer, usually at 90 degrees to the incident beam. A change in the scattered frequency with respect to the source is related to the vibrational frequencies of molecules. At the very most, the intensities of Raman lines are 0.001 % of the source. Lasers are the standard sources with Argon ion lasers being the most commonly used. Sciencetech offers several Raman spectrometers suited for different needs and budg- ets, ranging from single channel double monochromators to multichannel, triple monochromator systems with versatile multimode instruments.
Sciencetech Raman System RM-9040DA
The RM-9040DA is a complete modular system, specially designed for educational and research purposes. The 9040DA allows the study of solid, liquid and gas sam- ples with a variety of sample attachments. With its very low stray light level and high resolution, measurements very close to the Raman Line can be achieved making such de- terminations as the rotational modes of air molecules pos- sible.
The Raman RM-9040DA includes:
The 9040DA includes:
The 9040DA can also be fitted with one of Sciencetech's photodiode array detectors or cooled CCDs.
OTHER SINGLE CHANNEL SPECTROMETER SYSTEMS FOR RAMAN
RM-250 system consists of:
The double monochromator 9055DA in this system works in additive mode. Dispersed light exiting the first monochromator is dispersed again with both dispersions in the same direction. The 9055DA is a double 1/4 meter monochromator with resolution optimized for 500-700nm, corresponding to the wavelengths of most of the lasers used as Raman sources. It uses holographic gratings to minimize stray light.
RM-900 system consists of:
Multichannel Raman spectroscopy offers many ad- vantages for the user: It allows the recording of a large por- tion of the spectrum at once. Routine acquisition can be reduced from minutes and even hours to a few seconds. As a consequence of this fact other advantages arise:
RM-500 system consists of:
In this system, a double monochromator first sepa- rates a selected wavelength segment out of the incoming radiation. The segment is then passed onto a spectrograph stage where is dispersed over the multichannel detector sensitive area. Optional dual detector operation with flipping mirror allows the selection of the additional port in spectro- graph for photomultiplier detection.
Photodiode array detector system. 1024 elements, 25µm each. Detection range 200-1050nm. Specifications with 9040 monochromator:
Spectral coverage: 26 nm, 980 cm-1(@1800 l/mm, 514 nm)
(1024 elements) 78 nm,
2940 cm-1 (@600 l/mm, 514 nm)
Camera resolution: 0.026nm, 1cm-1(@1800 l/mm, 514 nm)
(25µm elements) 0.077 nm, 3 cm-1 (@600 l/mm, 514 nm)