DICTIONARY OF AUTOMOTIVE TERMS - Profile Pictures for ...

plutonium-239.
atomic clock:
A clock whose frequency of operation is controlled by the frequency of an
atomic or molecular process. The inversion of the ammonia molecule with
a frequency of 2.3786 x 10 10 Hz provides the basic oscillations of the
ammonia clock. The difference in energy between two states of a caesium
atom in a magnetic field giving a frequency of 9,192,631,770 Hz is the
basis of the caesium clock which has an accuracy of better than one in
10 13 .
atomic disintegration:
Natural decay of radioactive atoms, as a result of radiation, into
chemically different atomic products.
atomic displacement cross-section:
The probability of a neutron displacing an atom from its place in a
crystalline solid. Measured in barns as for other cross-sections. Important
in determining the lifetime of graphite moderator and structural parts of
reactors.
atomic frequency:
A natural vibration frequency in an atom used in the atomic clock
atomic plane:
A solid is crystalline because its atoms are ordered in intersecting planes
(i.e., atomic planes) corresponding to the planes of the crystal.
Also see
X-ray crystallography
atomic scattering:
The scattering of radiation, usually electrons or X-rays, by the individual
atoms in the medium through which it passes. The scattering is by the
electronic structure of the atom in contrast to nuclear scattering which is
by the nucleus.
atomic scattering factor: