Science paper reports synthesis of C13Cl2 on NaCl surfaces, confirming a half-Möbius electronic topology with helical orbitals periodic over four ring circulations.
Key Takeaways
C13Cl2 has sp and sp2 carbons whose p-orbitals allow a 90-degree twist per circulation, producing a half-Möbius topology distinct from both Hückel and classic Möbius systems.
Scanning tunneling microscopy mapped helical orbital densities directly; atomic force microscopy resolved enantiomeric geometries of the singlet states 12-P and 12-M.
Topology is reversibly switchable: STM tip interconverts the two half-Möbius singlets and a planar, topologically trivial triplet state via a helical pseudo-Jahn-Teller effect.
Berry phase for a quasiparticle on this ring is pi/2, not 0 (Hückel) or pi (Möbius), so standard aromaticity rules do not apply.
Ab initio multireference calculations were partly executed on quantum hardware, positioning the molecule as a benchmark for quantum computing beyond classical reach.
