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#charge transfer

Every note tagged #charge transfer, newest first — or browse the full archive.

July 5, 2026 Chemistry

One donor, one acceptor, one new band: push–pull chromophores and charge transfer

Aniline and nitrobenzene each absorb only in the ultraviolet. Bolt the amino donor and the nitro acceptor onto the same ring and a new band appears that neither parent owns — lower in energy and brighter than anything either shows alone. This post computes that emergence with TD-DFT, measures the charge-transfer character directly, and uses it to stress-test two density functionals against a failure mode one of them is famous for.

#quantum chemistry#TD-DFT#charge transfer#push-pull chromophores#UV-Vis#psi4#CAM-B3LYP
July 4, 2026 Chemistry

The colors on the palette are energy-level gaps: engineering pigments for permanence

A tube of paint is an electronic-structure problem plus a scattering problem, perceived by an eye. This post builds the mechanism-first taxonomy of color — conjugated π-systems, ligand-field d–d transitions, charge transfer, and semiconductor band gaps — leading with the modern synthetic pigments engineered to fix the lightfastness failures of their historic ancestors, then puts absorption and scattering back together with Kubelka–Munk.

#pigments#color#chromophores#lightfastness#charge transfer#ligand field#band gap#conjugation#Kubelka-Munk
pj Peter V. Johnston

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