We describe a new calculation of hyperfine contact interactions for ${\mathrm{Si}}^{29}$ lattice nuclei near shallow donors in silicon. The calculation utilizes Bloch functions for several energy bands throughout the Brillouin zone. The results are sufficiently accurate that for the first time it is possible to assign all experimental ${\mathrm{Si}}^{29}$ electron-nuclear double-resonance data to specific lattice sites.

• Received 27 March 1972

DOI:https://doi.org/10.1103/PhysRevLett.29.176