  We propose a Berry phase effect on the chiral degrees of freedom of a
triangular magnetic molecule. The phase is induced by adiabatically varying an
external electric field in the plane of the molecule via a spin-electric
coupling mechanism present in these frustrated magnetic molecules. The Berry
phase effect depends on spin-orbit interaction splitting and on the electric
dipole moment. By varying the amplitude of the applied electric field, the
Berry phase difference between the two spin states can take any arbitrary value
between zero and $\pi$, which can be measured as a phase shift between the two
chiral states by using spin-echo techniques. Our result can be used to realize
an electric field induced geometric phase-shift gate acting on a chiral qubit
encoded in the ground state manifold of the triangular magnetic molecule.
