  Theoretical and interpretative study on the subject of photodetachment of
H$^{-}$ near a partial reflecting surface is presented, and the absorption
effect of the surface is investigated on the total and differential cross
sections using a theoretical imaging method. To understand the absorption
effect, a reflection parameter $K$ is introduced as a multiplicative factor to
the outgoing detached-electron wave of H$^-$ propagating toward the wall. The
reflection parameter measures, how much electron wave would reflect from the
surface; K=0 corresponds to no reflection and K=1 corresponds to the total
reflection.
