Pulsed nuclear-magnetic-resonance (NMR) experiments on the ${\mathrm{F}}^{19}$ nuclei were performed on single crystals of fluoroapatite for the applied magnetic field along the hexagonal $c$ axis. An expression for the ${\mathrm{F}}^{19}$ free-induction decay was calculated by exactly diagonalizing the Hamiltonian of a closed linear chain of five spins with nearest- and next-nearest-neighbor dipolar interactions; the effects of other nuclei were included by using a Gaussian broadening function on the calculated multiplets. Good agreement between this theory and experiment was obtained.

• Received 20 September 1972

DOI:https://doi.org/10.1103/PhysRevB.7.924