Double-quantum transitions have been observed in the resonance depolarization spectrum of ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ implanted in a single-crystal beryllium host. The effect is observed at large depolarizing fields and gives a line unshifted by quadrupolar interactions.

• Received 2 April 1974

DOI:https://doi.org/10.1103/PhysRevLett.32.1133