The physical phenomena in which an extra electron is removed from a negative ion is called photo-detachment. Photo-detachment is important phenomena, used to find the structure of anions, particularly to find the electron affinities. In this paper, we present theoretically the induced effects in the photo-detached of triatomic anion H 3 À near hard reflecting wall or surface. For the photo-detachment process, a z-polarized coherent source of radiations (laser) is used to kick electrons from H 3 À anion in the domain of a hard reflecting surface. Imaging method is adopted to derive the generalized detached electron wave, differential cross-section and the total photo detachment cross-section analytically. Numerical solutions (simulations) for total electron flux and the total cross-section is presented. The electron flux, shows visible oscillations and hence the induced effect of surface in the interference. It is depicted that the reflecting hard wall strongly affects the flux and total photodetachment cross-section. The analytical results are extended for triiodide I 3 À anion numerically, which also show interference. The total photo detachment cross-section for I 3 À is calculated numerically and compared with cross-section of H 3 À .