Title: Chiral Discrimination in Biological Systems Induced by Spin-dependent van der Waals Interactions
When: Wednesday, July 24, 2024, 12:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor)
Speaker: Vladimiro Mujica, School of Molecular Sciences, Arizona State University, USA.
Space inversion symmetry in chiral molecules is broken. As a consequence, the electric and magnetic polarizabilities are coupled. We analyze the influence of this symmetry breaking in determining a chiral-discrimination mechanism mediated by spin-dependent van der Waals (vdW) interactions, arising from fluctuations on the magnetic moment of the molecule analogous to the electric dipole fluctuations responsible for the conventional form of vdW forces. This mechanism can be understood in terms of the Chiral-Induced Spin Selectivity (CISS) effect, which requires the inclusion of spin-orbit interaction (SOI). The CISS-mechanism is determined by a magnetic molecular response to electron transport in a chiral potential even in the absence of external magnetic fields. An alternative explanation, which does not require the inclusion of SOI, is based in exchange interactions associated with the antisymmetric character of the many-electron wavefunction. In either case, the emerging feature is a chiral-discrimination term that is added to the conventional London expression for vdW forces, which changes sign depending on whether the interaction between two chiral molecules, with two enantiomers, D and L, occurs either for the (DD) or (LL) pairs or for the (DL) one. This apparently simple result has profound consequences for biological system because it provides a way for long-distance chiral recognition based on vdW interactions. In a recent publication [1], we have successfully tested our model in providing an interpretation for chiral discrimination observed through Atomic Force Microscopy experiments. The potential applications of these results to the pharmacological industry, and in the area of quantum molecular sensors, are also discussed.
References
- Y. Kapon, Q. Zhu, S. Yochelis, R. Naaman, R. Gutierrez, G. Cuniberti, Y. Paltiel, V. Mujica; Probing chiral discrimination in biological systems using atomic force microscopy: The role of van der Waals and exchange interactions. J. Chem. Phys. 14 December 2023; 159 (22): 224702. https://doi.org/10.1063/5.0171742
