The processes of photo-detachment or ionization of stable molecules are widely investigated in modern atomic physics. But the present work deals with the calculation of the photo-detachment cross-sections in the case of negative quasi-molecules formed during collisions. The reaction H + H- + h omega -> H + H + e has been taken as an example of bound-free transitions in single-active-electron quasi-molecules. For simplicity, we discuss the one-dimensional case in the frame of the zero-range potential model.