FAQ:

Q. What is the spectral range?
A. There are two detectors available and each have a different range. The TGS (triglycine sulfate) detector has a range of 6000–350 cm^–1. The MCT (mercury cadmium telluride) detector provides more sensitivity and has a range of 650–11000 cm^–1.

Note: The MCT detector needs to be cooled with liquid nitrogen, which the user will need to obtain. Once cooled, it can operate for ~8 hours before refilling. Typically about 1 liter of N₂ is needed.



Q. What is the resolution limit?
A. The instrument can go down to a resolution as low as 0.5 cm^–1. A resolution of 8 cm^–1 is typical.



Q. Which detector should I use?
A. It depends on the sample. Routine samples (solids, liquids and solutions) are typically analyzed with the TGS detector while weakly absorbing samples, including thin films, monolayers and sub-monolayers on surfaces are best analyzed with the MCT detector.

Note: Surface spectra need to be collected using the Seagull accessory.



Q. How can I deal with water and carbon dioxide absorption?
A. The sample compartment can be evacuated to minimize water and CO₂ interference, but there will always be some signal from residual vapor. The sample compartment can be back-filled with dry air to minimize these interferences further.

Note: The air filter system is always off unless used. Its “thwack” causes vibrations which can interrupt the operation of nearby surface probe microscopes in the lab, so check with others before turning it on. It takes about 20 minutes for the air to dry once the filter is on.



Q. What sampling equipment is available?
A. There are sample holders for salt pellets, but the NCF does not provide pellet dies or halide salts. The Flood lab has a liquid and solution sample cell available for use (contact Eddie). For surface analysis, a reflectance accessory called the Seagull is available. There is also a polarizer available.



Q. What kind of software does the instrument use and what can it do?
A. It uses Opus, which is generally regarded as terrible. The pros are: Each spectrum file contains the sample and background spectra and interferograms (so you can always “dig up” those data), and you can export your data so you can analyze it using better software (e.g., Origin or Grams).

That being said, Opus can do all of the standard types of analysis (peak picking, peak area, spectral math, etc).



Q. Are there any health hazards to be aware of while operating this instrument?
A. Aside from knowing the hazards associated with your sample and liquid nitrogen handling, the only real concern is with the polarizer, which is coated with a toxic heavy metal. It is always a good practice to avoid touching optics, and in this case it can save you from heavy metal poisoning.