Scattering&Spectroscopy
Universität Wien

The Quantum Gyroscop

Sc2C2@C84 is a cluster-endohedral molecule. Experimental observations demonstrated a quantized rotation of the C2 molecule in a plane perpendicular to the rigid Sc-Sc axis. For a quantum state m ≥ 3 this rotation is free with a (classical) rotational frequency of
ωrotor = 1.02*1012 s-1 (for m=3), with the angular momentum
L = 3*(h/2*π) = 3.16*10-34 kgm2s-1

To see the C2 rotate inside its cage, click here.

If we attach the C84 cage on its surface to a linear molecule which allows for a free rotation around its axis (e.g. a poly-acetylene chain), the gravitational force m*g together with the radial distance r between the center of the cage and its surface creates a torque of
M = m*(g x r) = 1.22*10-32 Nm

According to Newtons second law this torque changes the angular momentum of the cage system, resulting in a precession of the cage around the linear molecule. The precession frequency is
ωP = r*m*g/L = 58.3 s-1
To see the quantum gyroscop precess, click here.

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We gratefully acknowledge the support of the FWF and the TMR, projects P14893 and HPRN-CT-2002-00192.

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