Determination of the pressure of the semimetal-semiconductor transition in the presence of a resonant acceptor level J.The hydrostatic pressure coefficient of Au acceptor levels Er in Si was measured by transient capacitance method. Under the pressure range of 0-8 kbar, the pressure coefficient a (Ee -Er)/ ap = -1.9 me V /kbar. The electron capture cross section of Au acceptor centers is independent of pressure within experimental accuracy. For defect levels with defect potential of Td symmetry, the uniaxial stress coefficient a (Ee -E r)l aF is isotropic and equal to one-third of corresponding hydrostatic pressure coefficient. By comparing the present result of hydrostatic pressure coefficient with the uniaxial stress coefficient reported by X. C. Yau, G. G. Qin, S. R. Zeng, and M. H. Yuan [Acta Phys. Sin. 33, 377 (1984)], one concludes that the defect potential is far from Td symmetry. Therefore, the Au acceptor levels are unlikely to have been originated by simple gold substitutional or interstitial configuration in Si.