The photoconductive response of several semiconducting diamonds was measured in the spectral range 0.8 to 4.7 &mgr; with crystal temperatures of 4.2° and 77°K. Photoconductive minima, most of which are not observed in the optical absorption spectrum of these diamonds, were recorded at 3.6, 3.5, 2.72, 2.65, 2.48, 2.41, 2.38, 2.35, 1.97, 1.87, 1.83, 1.78, 1.56, 1.44, 1.21, 1.05, 0.92, and 0.83 &mgr;, and minor features were recorded at 2.44, 2.25, 2.02, 1.33, and 1.13 &mgr;. Five activation energies, 0.21, 0.30, 0.37, 0.52, and 0.7 eV, for semiconducting diamonds have been observed. Good correlation is found between the photoconductive minima and the five activation energiesEAi(i=1,&cellip;, 5) through the termsEn=EAi+nEphwhereinEph= 0.165 eV, the energy of a Raman‐frequency phonon, andntakes integral values from 1 though 8. The minima may be explained as follows. Holes are excited to the valence band by the incident radiation. They lose energy mainly through the emission of Raman‐frequency phonons. When the energy relations are proper, holes are left in excited bound states at acceptor sites and do not contribute to the conduction process.