Astrophysics (Index)About

atomic excitation

(electron excitation, excitation)
(atoms with electrons above the ground state)

Atomic excitation (or electron excitation) is the state of an atom whose electrons are at a higher energy level than their ground state, i.e., a state of excitation. The term is also use for the attainment of such a higher state.

The atom's possible electron orbits (electron orbitals) are determined by quantum physics, and are quantized, or only allowed at certain energetic states. With sufficient energy, e.g., from a incoming photon, an electron can be moved to a higher state (a higher electron shell than they need to be in), i.e., an excited state. Such an excited atom has a tendency to emit one or more photons, moving toward its lowest state, i.e., its ground state, such a change being called electron relaxation. Radiated excitation is the energization of the electrons of an atom by a photon, i.e., bound-bound absorption. Gas excitation is the excitation of the atoms of a gas. The absorption of photons to excite atoms results in absorption lines and the subsequent return of atoms to less energetic states results in emission lines, e.g., hydrogen's Lyman series.

The term population inversion refers to a group of atoms where the majority are in an excited state.

(physics,atoms,quantum mechanics)
Further reading:

Referenced by pages:
absorption line
Auger effect
Balmer jump (BJ)
Boltzmann equation
Boltzmann Transport Equation (BTE)
carbon (C)
continuum emission
electron orbital
electron shell
emission coefficient (j)
emission line
electron volt (eV)
star formation feedback
line broadening
oscillator strength
state of excitation