Dynamics and relaxation of multiple quantum NMR coherences in a quasi-one-dimensional chain of nuclear spins $^{19}$F in calcium fluorapatite

Multiple quantum experiments on nuclear magnetic resonance on spins of $^{19}$F in calcium fluorapatite have been performed. It has been shown that more than 97% of the observed signal refers to the multiple quantum coherences of the zeroth and plus/minus second orders. The dependences of the intensities of these coherences on the time of the preparation period of the multiple quantum NMR experiment have been obtained. The dipole relaxation of multiple quantum coherences on the evolution period of the multiple quantum nuclear magnetic resonance experiment has been studied. A probe providing short radio-frequency pulses with the duration up to $0.3$ $\mu$s has been developed for experiments. The experimental results show that the studied system can be used for the transmission of quantum information and the study of the decoherence process in strongly correlated multispin clusters.