  We consider the adiabatic evolution of Kramers degenerate pairs of spin
states in a half-integer spin molecular magnet as the molecule is slowly
rotated. To reveal the full details the of the quantum evolution, we use
Majorana's parametrisation of a general state in the $2j+1$ dimensional Hilbert
space in terms of $2j$ Majorana points. We show that the intricate motion of
the Majorana points may be described by a classical hamiltonian which is of the
same form, but of quite different origin, as that which appears in the
spin-coherent-state path integral. As an illustration we consider molecular
magnets of the $j=9/2$ Mn4 family and compute the frequency with which the
magnetization varies. This frequency is generally different from the frequency
of the rotation.
