On Orientation Dependence of N2 Ionization: The Velocity Gauge Version   of Molecular Strong-Field Approximation
  We reply to the Comment of T. K. Kjeldsen and L. B. Madsen [e-print arXiv:physics/0508213] and acknowledge their criticism related to imperfect composition of our model 3sigma_g molecular state [V. I. Usachenko and S.-I. Chu, Phys. Rev. A 71, 063410 (2005)]. However, we cannot agree with the authors suggesting this critique also as an irrefutable argument and/or evidence in support and justification of their opposite and incorrect (viz. inconsistent with relevant experiment) orientation dependence of N2 ionization rate calculated within the velocity gauge version of molecular strong-field approximation. We disclose the actual reason of the contradiction and demonstrate that appropriately composed 3sigma_g state (modified according to the Comment's critique) rather confirms the alternative earler calculation [A. Jaron-Becker, A. Becker and F. H. M. Faisal, Phys. Rev. A 69, 023410 (2004)] suggesting correct orientation dependence of N2 ionization, contrary to respective results of the Comment's authors applying the same approach and procedure of 3sigma_g composition. 
Vladimir I. Usachenko