Figure 1.

Vibrational modes of common biomolecular bonds - Inherent vibrational motion of molecules gives rise to distinct, fingerprint-like absorption bands in the mid-infrared region. Schematic shows different stretching or bending vibrational bands commonly encountered in biological samples. Infrared spectroscopy is sensitive to the presence of many chemical functional groups (structural fragments) in molecules, and taken together the set of vibration modes are unique for every molecular configuration.