Originally 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.

Table of contents
1 Types of spectroscopy
2 Energy of photons
3 kinetic energy of electrons
4 kinetic energy of ions or molecules
5 vibrational energy
6 Other Topics

Types of spectroscopy

Energy of photons

kinetic energy of electrons

kinetic energy of ions or molecules

vibrational energy

Other Topics