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Excited Atom

Astronomy  Evolved star  Exclusion principle

Excited Atom
An atom in which an electron has moved from a lower to higher orbit.
Extinction ...

Some excited atomic states take so long to emit a photon that the spectral lines associated with these transitions are never seen in terrestrial laboratories, where collisions always knock the atom into another energy state before it can emit any radiation.

excited atom An atom with one or more of its bound electrons in an increased energy level. exclusive OR circuit A circuit which produces an output signal when any one, but not more than one, input is in its prescribed state. Also called AND-NOT gate.

extremely highly excited atoms are called Rydberg atoms (Rydberg was an early systematizer of atomic spectra). These atoms are huge (the size of viruses for the largest) and fragile but interact very strongly with radiation.

11. Why do excited atoms absorb and reemit radiation at characteristic frequencies? HINT ...

Excited Atom
An atom in which an electron has moved from a lower to higher orbit.
The dimming of light by intervening material; commonly, dimming by the interstellar medium.
A short focal length lens used to enlarge the image in a telescope; the lens nearest the eye
F ...

CHARACTERISTIC X-RAY - X-ray emitted from an excited atom when an outer-shell (e.g. L) electron jumps in to fill an inner-shell (e.g. K) vacancy. It has energy characteristic of the atom and can therefore be used for analytical purposes.

So now we have excited atomic oxygen in the upper levels of the atmosphere. That excited atomic oxygen can only stay excited so long. Then it drops to a lower energy level.

In ordinary light sources the many excited atoms or molecules emit light independently and in many different colors (wavelengths).

(a) The spontaneous ionization of excited atoms, ions, or molecules, as in the Auger effect. see Auger Effect; Ionization [DC99]
(b) A phenomenon occurring when a discrete double-excitation state of an atom lies in the ground-state continuum.

An excited atom, one in a high energy state, has an electron in a higher energy orbit than normal. Nothing likes having more energy than it needs, so the electron will drop to a lower energy state. The difference in energy between the two levels is emitted as electromagnetic radiation, a photon.

An ablating meteoroid thus leaves behind it a trail of highly excited atoms, which then de-excite to produce the streak of light seen as a meteor.

Most meteors typically measure 1m across and 20km long, and consist of a cylinder of excited atoms and molecules. They are normally seen between 120 and 80km above Earth's surface.

As long as the atom has this extra energy it is referred to as being "excited". To get back down to the lowest energy level, the electron has to get rid of the energy and does so by emitting light with the appropriate energy to make the transition. Now it is just a plain unexcited atom again.

This causes an electron to be promoted into a higher energy level, and the atom, element or molecule is said to be in an excited state. Emission lines occur when the electrons of an excited atom, element or molecule move between energy levels, returning towards the ground state.

See also: See also: Astro, Earth, Radiation, Emission, Atmosphere

Astronomy  Evolved star  Exclusion principle

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