Concerted Proton Transfer

We stumbled on a very curious observation in the summer of 2018 with DABQDI molecules provided by Olivier Siri‘s team.

ncAFM image of 26 molecule chain. Unfiltered data.
STM chain manipulation
Repeated manipulations with STM tip are capable of dragging a DABQDI chain around the Au111 surface.

While evaluating its experimental suitability for 1d coordination with metals, which has already proven to be fruitful, we noticed the molecules forming chain-like structures even before we introduced metal adatoms.

The low temperature SPM results are sublime: unusual mechanical stability, distinctive intermolecular bonding, and near-Fermi electronic states lighting up at the ends of the chains.

It took an extraordinary cast of theorists hailing from Pavel’s core group, FZU, Charles, Reykjavik, & Madrid Universities to unravel this puzzle and explain these observations as concerted proton tunneling causing a delocalization of electrons.

“Significance of Nuclear Quantum Effects in Hydrogen Bonded Molecular Chains”, ACS Nano, 2021. 10.1021/acsnano.1c02572

ArXiv link