We study the questions of the existence and mass of the proposed d'(IJ(P) =
OO-) dibaryon in the quark-delocalization, color-screening model. The tran
sformation between physical and symmetry bases has been extended to the cas
es beyond the SU(2) orbital symmetry. Using parameters fixed by baryon prop
erties and NN scattering, we find a mild attraction in the IJ(P) = OO- chan
nel, but it is not strong enough to form a deeply bound state as proposed f
or the d' state. Nor does the (isospin) 1=2 N Delta configuration have a de
eply bound state. These results show that if a narrow dibaryon d' state doe
s exist, it must have a more complicated structure.