  Two-photon ionization of an alkali-metal atom in the presence of a uniform
electric field is investigated using a standardized form of local frame
transformation and generalized quantum defect theory. The relevant long-range
quantum defect parameters in the combined Coulombic plus Stark potential is
calculated with eigenchannel R-matrix theory applied in the downstream
parabolic coordinate $\eta$. The present formulation permits us to express the
corresponding microscopy observables in terms of the local frame
transformation, and it gives a critical test of the accuracy of the Harmin-Fano
theory permitting a scholastic investigation of the claims presented in Zhao
{\it et al.} [Phys. Rev. A 86, 053413 (2012)].
