FACTOID # 50: Libya is the only country with a single-coloured flag.
 
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Encyclopedia > Selection rules

In physics, especially in the context of quantum mechanics, a selection rule is a condition constraining the physical properties of the initial system and the final system that is necessary for a process to occur with a nonzero probability. The selection rules often say that a quantum number is conserved or changed by plus one or minus one unit (because the interaction allows one unit of the quantum number to be carried away by another particle).


See also: angular momentum coupling


  Results from FactBites:
 
Hydrogen Schrodinger Equation (460 words)
These are the selection rules for an electric dipole transition.
Another approach to the selection rules is to note that any electron transition which involves the emission of a photon must involve a change of 1 in the angular momentum.
An exception to this last selection rule it that you cannot have a transition from j=0 to j=0; i.e., since the vector angular momentum must change by one unit in a electronic transition, j=0 -> 0 can't happen because there is no total angular momentum to re-orient to get a change of 1.
RULES FOR ALTERNATIVE DISPUTE RESOLUTION (9073 words)
The rules of pleading and practice in civil cases shall not apply, and the proceedings shall be informal as directed by the Chair.
This rule does not require exclusion when the evidence is offered for another purpose, such as proving bias or prejudice of a witness, negating a contention of undue delay, or proving an effort to obstruct a criminal investigation or prosecution.
Selection of the advisor shall be based upon the education, training and experience necessary to assist the parties in resolving their dispute.
  More results at FactBites »


 

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