Tunnel ionization belongs to the fundamental processes of atomic physics. The
so-called two-step model, which describes the ionization as instantaneous
tunneling at the electric field maximum and classical motion afterwards with
zero exit momentum, is commonly employed to describe tunnel ionization in
adiabatic regimes. In this contribution, we show by solving numerically the
time-dependent Schr\"odinger equation in one dimension and employing a virtual
detector at the tunnel exit that there is a nonvanishing positive time delay
between the electric field maximum and the instant of ionization. Moreover, we
find a nonzero exit momentum in the direction of the electric field. To extract
proper tunneling times from asymptotic momentum distributions of ionized
electrons, it is essential to incorporate the electron's initial momentum in
the direction of the external electric field
