One of the strangest and most fascinating findings in modern molecular physics is that handedness — simple geometric handedness — can influence the quantum behaviour of electrons. Chiral molecules, which come in left- and right-handed forms, have been shown to act as spin filters: when electrons pass through them, one spin orientation is transmitted more efficiently than the other. This phenomenon, known as the Chiral-Induced Spin Selectivity (CISS) effect, has now been observed in systems ranging from DNA to peptides and helicene-based molecules.
What makes CISS so intriguing is that conventional explanations struggle to account for its strength. In light organic molecules, ordinary spin–orbit coupling is usually far too weak to explain the large spin polarizations seen in experiments. That suggests something deeper is at work. In this paper, I explore the idea that the effect is rooted not primarily in chemistry, but in geometry itself. When an electron is constrained to move along a helical path, the twist of that path — its torsion — naturally enters the spin dynamics through the spin connection of the rotating frame. In other words, the geometry of the molecule generates a spin-dependent coupling simply because the electron is moving through a curved, twisted structure.
The mathematics shows that this geometric mechanism has exactly the right qualitative features. The spin splitting vanishes when the electron is not moving, which matches the fact that CISS is a transport effect rather than an equilibrium one. It reverses sign when the handedness of the molecule is reversed, which is one of the clearest experimental signatures of CISS. And when the resulting band splitting is carried through a simple Landauer transport model, it leads naturally to spin-dependent transmission and a clean geometry-first scaling law controlled by torsion and electron wavevector.
From the perspective of the VERSF framework, this result is especially interesting because it supports a broader idea: physical structure does not merely host processes, it helps determine which processes are admissible. In this case, the chiral molecule is not just a passive channel for electrons. Its geometry reshapes the transition landscape itself, favouring one spin pathway over another.
And that leads to a striking possibility.
If geometry alone can bias quantum outcomes in a molecular system, then the role of structure in physics may be deeper than we usually assume. The shape of a system may not merely influence what happens inside it — it may actively determine which possibilities are available at all.
The CISS effect may therefore be more than a curiosity of molecular electronics. It may be a glimpse of a broader principle: that the architecture of physical systems — their curvature, topology, and symmetry — helps write the rules of the processes that occur within them.
In that sense, the corkscrew shape of a molecule is doing something profound. It is not just guiding electrons through space.
It is quietly deciding which quantum futures are allowed to unfold.