Selection Rule

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:

    It is the highest and most legitimate pride of an Englishman to have the letters M.P. written after his name. No selection from the alphabet, no doctorship, no fellowship, be it of ever so learned or royal a society, no knightship,—not though it be of the Garter,—confers so fair an honour.
    Anthony Trollope (1815–1882)

    The condition that gives birth to a rule is not the same as the condition to which the rule gives birth.
    Friedrich Nietzsche (1844–1900)