Spectroscopy

Orginally a spectrum was what was observed when white light was dispersed through a prism. Soon the term referred to a plot of light intensity as a function of frequency or wavelength. Planck later realized that frequency represents electromagnetic energy.

E = h ν

Today the term has been generalized even further to include any data that are the result of a study where an energy (or frequency) is systematically varied

The recording and studying of spectrum of energy levels in atoms or molecules in the physical sciences[?] is called spectroscopy. A device for recording a spectrum is a spectrometer or spectrophotometer. The latter term is used when an optical spectrum is recorded by the device.

Types of spectroscopy

Energy of photons

• electromagnetic spectroscopy - The study electomagnetic radiation spectra given off or absorbed by atoms or molecules changing energy levels.
• Atomic absorption spectroscopy
• infra-red spectroscopy - The study of spectra showing infra-red radiation absorbed by atoms or molecules making them vibrate.
• UV/VIS spectroscopy
• Mossbauer spectroscopy - Measures the absorption of gamma-rays by atoms bound in a solid as a function of gamma-ray energy.
• Nuclear magnetic resonance - Measures the resonant absorption of RF radiation by nuclei in a strong magnetic field. Absorption peaks correspond to transitions in the nuclear spin states of the nuclei.
• Electron spin resonance spectroscopy
• Raman spectroscopy The study of spectra caused by the scattering and change in frequency of light due to the transition between vibrational/rotational energy levels in molecules.
• Stark spectroscopy
• Fluorescence spectroscopy[?]
• X-ray fluorescence
• Circular Dichroism
• Magnetic Circular Dichroism

kinetic energy of electrons

• X-ray photoelectron spectroscopy
• Electron energy loss spectroscopy
• Auger electron spectroscopy - The analysis of the energies of the stimulated emission of Auger electrons

kinetic energy of ions or molecules

• mass spectrometry - The study of the mass of molecules or atoms, measured by how much they bend as they are exposed to a magnetic field

vibrational energy

• Acoustic spectroscopy[?]
• Dynamic Mechanical Spectroscopy
• Dielectric Spectroscopy[?]

Other Topics

• Rotational spectroscopy[?]
• Vibrational spectroscopy

• Fourier transform spectroscopy - An efficient method for collecting various spectra. Frequently applied to infra-red spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) Spectroscopy.
• Force spectroscopy - An AFM-based analytical technique