Reflection Through A Plane Containing The Internuclear Axis
There are an infinite number of planes containing the internuclear axis and hence there are an infinite number of possible reflections. For any of these planes, molecular terms with Λ > 0 always have a state which is symmetric with respect to this reflection and one state that is antisymmetric. Rather than labelling those situations as, e.g., 2Π±, the ± is omitted.
For the Σ states, however, this two-fold degeneracy disappears, and all Σ states are either symmetric under any plane containing the internuclear axis, or antisymmetric. These two situations are labeled as Σ+ or Σ−.
Read more about this topic: Molecular Term Symbol
Famous quotes containing the words reflection, plane and/or axis:
“Water. Its sunny track in the plain; its splashing in the garden canal, the sound it makes when in its course it meets the mane of the grass; the diluted reflection of the sky together with the fleeting sight of the reeds; the Negresses fill their dripping gourds and their red clay containers; the song of the washerwomen; the gorged fields the tall crops ripening.”
—Jacques Roumain (1907–1945)
“It was the most ungrateful and unjust act ever perpetrated by a republic upon a class of citizens who had worked and sacrificed and suffered as did the women of this nation in the struggle of the Civil War only to be rewarded at its close by such unspeakable degradation as to be reduced to the plane of subjects to enfranchised slaves.”
—Anna Howard Shaw (1847–1919)
“A book is not an autonomous entity: it is a relation, an axis of innumerable relations. One literature differs from another, be it earlier or later, not because of the texts but because of the way they are read: if I could read any page from the present time—this one, for instance—as it will be read in the year 2000, I would know what the literature of the year 2000 would be like.”
—Jorge Luis Borges (1899–1986)