Experimental results on excitons bound to neutral doubly ionizable acceptors are presented and discussed. In particular, the bound-exciton emission was investigated as a function of the concentration of the natural acceptor in GaSb and as a function of uniaxial stress. The final state after decay of the bound exciton is split by the jj coupling of the holes. From the stress dependence we determine the values of the three different deformation-potential constants that must be assumed for the ionized acceptor, neutral acceptor, and the bound-exciton states, i.e., one-, two-, and three-hole states, respectively. The reduction factors for the uniaxial-deformation-potential constants of the bound holes were deduced from simultaneous measurement of the free-exciton reflection and the photoluminescence under uniaxial stress. These factors show a strong dependence on the binding energy of the bound holes. The magnetic field data can be interpreted completely with this model. © 1978 The American Physical Society.