In physics and chemistry a selection rule, or transition rule, formally constrains the possible transitions of a system from one state to another. Selection rules have been derived for electronic, vibrational, and rotational transitions. The selection rules may differ according to the technique used to observe the transition.
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Famous quotes containing the words selection and/or rule:
“Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.”
—Konrad Lorenz (1903–1989)
“Without doubt God is the universal moving force, but each being is moved according to the nature that God has given it.... He directs angels, man, animals, brute matter, in sum all created things, but each according to its nature, and man having been created free, he is freely led. This rule is truly the eternal law and in it we must believe.”
—Joseph De Maistre (1753–1821)