A team of researchers from Manchester, Oxford, Regensburg, Lausanne and IBM Research Europe used atom-manipulation tools to create a novel 13-carbon ring molecule, C13Cl2, with a half-Möbius electron-orbital topology by selectively removing chlorine atoms from a fully chlorinated C13Cl10 ring.

The molecule was assembled on a gold surface at cryogenic temperatures, precisely manipulated with atomic force microscopy and scanning tunnelling microscopy to shape its topology and map electron distributions.

Imaging and experiments revealed a corkscrew-like electronic structure that twists 90 degrees per circuit, requiring four loops to return to the starting phase, a topology not observed in chemistry before.

The topology can be reversibly switched among clockwise-twisted, counterclockwise-twisted, and untwisted states, demonstrating controllable electronic topology in a single molecule.

Atomic force microscopy and scanning tunnelling microscopy confirmed the half-Möbius geometry and showed a twisted lowest-unoccupied molecular orbital in the half-Möbius singlet state versus a planar untwisted orbital in the triplet state.

Bias-voltage control via the microscope tip enables the molecule to shift among left-handed half-Möbius, right-handed half-Möbius, and planar configurations, illustrating switchable topology on demand.

A small electromagnetic pulse demonstrated controllable topology, enabling reversible switching between twisted and untwisted states.

Quantum computing played a central role in validating the electronic configuration and topology, with simulations run on both conventional computers and IBM's quantum processor to understand the system.

The work showcases two advances: engineered electronic topology in chemistry and practical quantum simulations that tackle molecular-scale systems beyond classical capabilities.

Hybrid quantum-classical workflows and 72-qubit quantum calculations contributed to capturing deeply entangled electron interactions and the helical pseudo-Jahn–Teller effect that drives the topology.

The half-Möbius topology imposes unique boundary conditions and Berry phase characteristics, which could influence magnetic, electronic, and spin-dependent properties.

The study points to future prospects for more complex, topology-switchable molecules and networks, expanding topology-driven chemistry.