Prof. Ronnie Kosloff
Seminar Title: Deciphering the Mechanism of Animal Magnetic Navigation: Geometric Phase
Abstract: Magnetic sensing is commonly found in migratory species, and was shown to depend on ambient blue/UV light. We hypothesize that visual opsin with a de-protonated retinal Schiff base as a chromophore can function as a directional magnetic sensor. This photoreceptor protein is embedded in a stack of oriented membranes aligned to the visual axis. The absorption in the blue/UV region of the spectrum is due to the deprotonation of the Schiff base moiety. This form gives rise to n-π∗ excited states which enable intersystem crossing with the bright π − π∗ excited state. As a result, magnetic sensitive triplet electronic states are formed. These triplets are the source of magnetic sensing. A quantum phenomena based on the geometric phase accumulated by the rotation of the molecule around the magnetic field axis operates as an interformeter. The actual double bond isomerization of the retinal chromophore in the excited state around the magnetic axis is the source of magnetic sensing. Magnetic directional sensitivity is then superimposed on the blue/UV visual signal.
*tum phenomena based on the geometric phase accumulated by the rotation of the molecule around the magnetic field axis operates as an interformeter. The actual double bond isomerization of the retinal chromophore in the excited state around the magnetic axis is the source of magnetic sensing.
