A wavelength of energy that is also called a reciprocal centimeter. Wavenumbers are obtained when frequency is expressed in Hertz and the speed of light is expressed in cm/s. This unit is commonly used in infrared spectroscopy
Interactive Learning Paradigms Incorporated ILPI (Knowledge at the Speed of Light), The MSDS Hyper Glossary (Home Page of the Material Safety Data Sheet Hyper Glossary), ILPI, NJ, USA 2011. http://www.ilpi.com/msds/ref/index.html, (MSDS - Amer) {448}