spectroscopy (pronounced: [r?.m?N] S-) is a spectroscopic technique used in
condensed matter physics and chemistry
to study vibrational, rotational, and other low-frequency modes in a system. It relies on inelastic scattering, or Raman scattering, of monochromatic light,
usually from a laser
in the visible, near infrared, or near ultraviolet range. The laser
light interacts with phonons
or other excitations in the system,
resulting in the energy
of the laser
photons being shifted up or down. The shift in energy gives information about the phonon modes in the system.
Infrared spectroscopy yields
similar, but complementary, information.