We determine the asymptotics of the two-point correlation function for quan
tum systems with half-integer spin which show chaotic behaviour in the clas
sical limit using a method introduced by Bogomolny and Keating. For time-re
versal-invariant systems we obtain the leading terms of the two-point corre
lation function of the Gaussian symplectic ensemble. Special attention has
to be paid to the role of Kramers' degeneracy.