Stark Effect
In the presence of a static external electric field the 2J+1 degeneracy of each rotational state is partly removed, an instance of a Stark effect. For example in linear molecules each energy level is split into J+1 components. The extent of splitting depends on the squares of the electric field strength and of the dipole moment of the molecule. In principle this provides a means to determine the value of the molecular dipole moment with high precision. Examples include carbonyl sulfide, OCS, with μ = 0.71521 ± 0.00020 Debye. However, because the splitting depends on μ2, the orientation of the dipole must be deduced from quantum mechanical considerations.
Read more about this topic: Rotational Spectroscopy
Famous quotes containing the words stark and/or effect:
“Utopias are presented for our inspection as a critique of the human state. If they are to be treated as anything but trivial exercises of the imagination. I suggest there is a simple test we can apply.... We must forget the whole paraphernalia of social description, demonstration, expostulation, approbation, condemnation. We have to say to ourselves, “How would I myself live in this proposed society? How long would it be before I went stark staring mad?””
—William Golding (b. 1911)
“That when that knot’s untied that made us one,
I may seem thine, who in effect am none.
And if I see not half my dayes that’s due,
What nature would, God grant to yours and you;”
—Anne Bradstreet (c. 1612–1672)