  In the epsilon-regime of lattice QCD one can get an accurate measurement of
the pion decay constant F_pi by monitoring how just one single Dirac operator
eigenvalue splits into two when subjected to two different external vector
sources. Because we choose imaginary chemical potentials our Dirac eigenvalues
remain real. Based on the relevant chiral Random Two-Matrix Theory we derive
individual eigenvalue distributions in terms of density correlations functions
to leading order in the finite-volume epsilon-expansion. As a simple byproduct
we also show how the associated individual Dirac eigenvalue distributions and
their correlations can be computed directly from the effective chiral
Lagrangian.
