studies are not usually focused on chemical interactions, but rather on fundamental chemical properties. Because of the extremely low temperatures, diagnosing the chemical status is a major issue when studying low temperature physics and chemistry. The primary techniques in use today are optical - many types of spectroscopy are available, but these require special apparatus with vacuum windows that provide room temperature access to cryogenic processes. See also Thermochemistry Cryogenics Bose–Einstein condensate References Moskovits, M., and Ozin, G.A., (1976) Cryochemistry, J. Wiley & Sons, New York Dillinger, J. R. (1957). Low temperature physics & chemistry (edited by Joseph R. Dillinger.) Madison, Wisconsin: University of Wisconsin Press. Naduvalath, B. (2013). "Ultracold molecules." Phillips, W. D. (2012). "Laser cooling" Parpia, J. M., & Lee, D.M. (2012). "Absolute zero" Hasegawa, Y., Nakamura, D., Murata, M., Yamamoto, H., & Komine, T. (2010). "High-precision temperature control and stabilization using a cryocooler. Review of Scientific Instruments", doi:10.1063/1.3484192 Physical chemistry Thermochemistry Cryobiology Condensed matter physics Astrochemistry