In molecular physics, the molecular term symbol is a shorthand expression of the group representation and angular momenta that characterize the state of a molecule, i.e. its electronic quantum state which is an eigenstate of the electronic molecular Hamiltonian. It is the equivalent of the term symbol for the atomic case. However, the following presentation is restricted to the case of homonuclear diatomic molecules, or symmetric molecules with an inversion centre. For heteronuclear diatomic molecules, the u/g symbol does not correspond to any exact symmetry of the electronic molecular Hamiltonian. In the case of less symmetric molecules the molecular term symbol contains the symbol of the group representation to which the molecular electronic state belongs.
It has the general form:
- S is the total spin quantum number
- Λ is the projection of the orbital angular momentum along the internuclear axis
- Ω is the projection of the total angular momentum along the internuclear axis
- u/g is the parity
- +/− is the reflection symmetry along an arbitrary plane containing the internuclear axis
Read more about Molecular Term Symbol: Λ Quantum Number, Ω and Spin–orbit Coupling, Reflection Through A Plane Containing The Internuclear Axis, Reflection Through An Inversion Center: U and G Symmetry, Alternative Empirical Notation
... He was the first to define the term milieu intérieur (now known as homeostasis, a term coined by Walter Bradford Cannon) ... who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite ... Thomas Henry Huxley (1825–1895), English biologist and coiner of the term agnosticism ...
Famous quotes containing the words symbol and/or term:
“In a symbol there is concealment and yet revelation: here therefore, by silence and by speech acting together, comes a double significance.... In the symbol proper, what we can call a symbol, there is ever, more or less distinctly and directly, some embodiment and revelation of the Infinite; the Infinite is made to blend itself with the Finite, to stand visible, and as it were, attainable there. By symbols, accordingly, is man guided and commanded, made happy, made wretched.”
—Thomas Carlyle (17951881)
“I shall not seek and I will not accept, the nomination of my party for another term as your President.”
—Lyndon Baines Johnson (19081973)