Astrophysics (Index)About

state of excitation

(energy level of something above the minimum)

A state of excitation is the state of a quantum system (atom, molecule, nucleus) at a higher energy level than the ground state (minimum energy level). For atoms, these are thought of as electrons in orbits further from the nucleus than they need to be (higher electron shells). Spectral lines result from numerous atoms undergoing some particular transition between states of excitation through absorption or emission of a photon (atomic excitation).

For a collection of atoms, e.g., a gas, the percentages of the gas at each state of excitation is of interest, because of its relation to temperature and to characteristics of the spectral lines (line broadening), allowing the study of spectral lines to be used to determine temperature, through the Boltzmann equation.

(physics,quantum mechanics,atoms)
Further reading:

Referenced by pages:
atomic excitation
Boltzmann equation
degeneracy weight
electron orbital
false vacuum
forbidden line
ground state
helium (He)
ionizing radiation
line blanketing
Lyman-Werner photon
quantum number