  Sturmian eigenstates specified by stationary scattering boundary conditions
are particularly useful in contexts such as forming simple separable two
nucleon t matrices, and are determined via solution of generalised eigenvalue
equation using real and symmetric matrices. In general, the spectrum of such an
equation may contain complex eigenvalues. But to each complex eigenvalue there
is a corresponding conjugate partner. In studies using realistic
nucleon--nucleon potentials, and in certain positive energy intervals, these
complex conjugated pairs indeed appear in the Sturmian spectrum. However, as we
demonstrate herein, it is possible to recombine the complex conjugate pairs and
corresponding states into a new, sign--definite pair of real quantities with
which to effect separable expansions of the (real) nucleon--nucleon reactance
matrices.
