Abstract
A first-principle calculation of |ψ(0)|2 is presented for P, As, and Sb impurities in Si. The agreement with experiment is excellent for P, poor for As and Sb. An attempt was then made to analyze the electron-nuclear-double-resonance results for the transferred hyperfine resonance of P impurities in Si. While it was not possible to unambiguously identify the various lines, it is possible to group the resonance lines such that groups of lines can be identified with groups of sites.