  The reaction $\gamma d\to \pi^+ nn$ is calculated up to order $\chi^{5/2}$ in
chiral perturbation theory, where $\chi$ denotes the ratio of the pion to the
nucleon mass. Special emphasis is put on the role of nucleon--recoil
corrections that are the source of contributions with fractional power in
$\chi$. Using the known near threshold production amplitude for $\gamma p\to
\pi^+ n$ as the only input, the total cross section for $\gamma d\to \pi^+ nn$
is described very well. A conservative estimate suggests that the theoretical
uncertainty for the transition operator amounts to 3 % for the computed
amplitude near threshold.

Nuclear Theory;High Energy Physics - Phenomenology