Research: Magnetic Currents in DNA-Molecules Understood with New Theory

2019-11-12

Jonas Fransson, Professor at Uppsala University, has developed a model for how electrons move in helix shaped molecules when they are affected by external forces. In the model is for the first time taken regard to the internal interactions between the electrons.

In the new model is made clear how electron currents, I, are affected by external forces, in form of for example magnetic fields, B, in helix shaped molecules. Image: Jonas Fransson.

As early as two decades ago magnetic currents in helix shaped molecules were discovered, for example in DNA-molecules. The magnetic currents have since then puzzled the researchers but also given rise to theories about how for example birds navigate on Earth.

A number of different experiments have been done where helix shaped molecules have been exposed to some form of strong external influence, so called non-equilibrium, and one has been able to measure the magnetic currents which have been generated. The experiments have shown that the electron currents are strongly affected by magnetic fields, which is typical for magnetic materials and molecules, since they have an internal magnetic moment which may be affected by external forces. But there is though no evidence that in the helix shaped molecules there is an internal magnetic moment, which has hampered the theory development of the experimental results.

Until now the theory of the origin of the magnetic activity has been modelled with the help of so called single electron theory. The theory has ignored the interactions, or correlations, between the electrons. With this theory it is possible to explain the origin of the magnetic activity by symmetry violations due to the helix shaped geometry, the spin of the electrons and that the system is out of equilibrium. But the theory has not been able to answer how the electron currents are changed as a reaction to exterior forces.

Jonas Fransson has now suggested a new model where regard is taken to the internal interactions of the electrons. The model gives answers to how the electron currents are affected by external forces and gives rise to different strong fluxes depending on how these are directed.

Article reference

J. Fransson (2019); Chirality-Induced Spin Selectivity: The Role of Electron Correlations, J. Phys. Chem. Lett. 2019. Publication Date: October 28, 2019, DOI: 10.1021, https://doi.org/10.1021/acs.jpclett.9b02929

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