Posts Tagged ‘Jahn–Teller effect’
Thursday, April 25th, 2019
Previously, I explored (computationally) the normal vibrational modes of Co(II)-tetraphenylporphyrin (CoTPP) as a “flattened” species on copper or gold surfaces for comparison with those recently imaged[1]. The initial intent was to estimate the “flattening” energy. There are six electronic possibilities for this molecule on a metal surface. Respectively positively, or negatively charged and a neutral species, each in either a low or a high-spin electronic state. I reported five of these earlier, finding each had quite high barriers for “flattening” the molecule. For the final 6th possibility, the triplet anion, the SCF (self-consistent-field) had failed to converge, but for which I can now report converged results.†
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References
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J. Lee, K.T. Crampton, N. Tallarida, and V.A. Apkarian, "Visualizing vibrational normal modes of a single molecule with atomically confined light", Nature, vol. 568, pp. 78-82, 2019. http://dx.doi.org/10.1038/s41586-019-1059-9
Tags:019-1059-9, 10.1038, Biomolecules, Chelating agents, chemical bonding, Chemical compounds, Chemistry, Coordination chemistry, Coordination complex, Copper, copper metal surface, Cu–CO, E-type, energy, free energy, higher energy, impossible free energy, Inorganic chemistry, Jahn–Teller effect, lowest energy electronic state, Metabolism, metal, metal surface, modest planarisation energy, Molecule, Natural sciences, Physical sciences, planarisation, Porphyrin, reasonable energy, Resonance, Solid-state chemistry, sufficient energy, Teller, Tetraphenylporphyrin
Posted in Interesting chemistry | 1 Comment »
Saturday, May 30th, 2015
I am on a mission to persuade my colleagues that the statistical analysis of crystal structures is a useful teaching tool. One colleague asked for a demonstration and suggested exploring the classical Jahn-Teller effect (thanks Milo!). This is a geometrical distortion associated with certain molecular electronic configurations, of which the best example is illustrated by octahedral copper complexes which have a d9 electronic configuration. The eg level shown below is occupied by three electrons and which can therefore distort in one of two ways to eliminate the eg degeneracy by placing the odd electron into either a x2-y2 or a z2 orbital. Here I explore how this effect can be teased out of crystal structures.
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Tags:basic search, Chemical bond, chemical bonding, Chemistry, classical Jahn-Teller, clear Jahn-Teller, Coordination chemistry, Coordination complex, Copper(II) nitrate, dynamic Jahn-Teller, Edward Teller, Inorganic chemistry, Jahn-Teller, Jahn–Teller effect, Metal ions in aqueous solution, search criteria, Technology/Internet, Transition metals
Posted in Chemical IT, crystal_structure_mining | 1 Comment »