Tuesday, November 16, 2010
Finding the lost twin
This beautiful picture is on the cover of A Chemist's guide to Valence Bond Theory by Shaik and Hiberty. It summarises the main idea in a paper, The Twin-Excited State as a Probe for the Transition State in Concerted Unimolecular Reactions: The Semibullvalene Rearrangement.
It illustrates how the use of diabatic states (K1 and K2) based on chemical intuition can lead to adiabatic potential energy surfaces with complex structure. Furthermore, it illustrates the notion of an excited state (K1 - K2) which is a "twin state" to the ground state, K1+K2. The relevant vibrational frequency is higher in the excited state than in the ground state.
An earlier post discussed the analogous picture for benzene.
Subscribe to:
Post Comments (Atom)
Emergence and protein folding
Proteins are a distinct state of matter. Globular proteins are tightly packed with a density comparable to a crystal but without the spatia...
-
Is it something to do with breakdown of the Born-Oppenheimer approximation? In molecular spectroscopy you occasionally hear this term thro...
-
If you look on the arXiv and in Nature journals there is a continuing stream of people claiming to observe superconductivity in some new mat...
-
I welcome discussion on this point. I don't think it is as sensitive or as important a topic as the author order on papers. With rega...
No comments:
Post a Comment