Non-cyclic geometric phase of nuclear quadrupole resonance signals of powdered samples

► Analytical expressions for non-cyclic geometric phases of NQR signals depending on the duration of r.f. pulses and the frequency detuning for the spins I=1 and 3/2 for a separate crystallite were obtained. ►The simulations of the signal phases were performed. ►An alternative variant of the nutation experiment aimed at obtaining the asymmetry parameter η from locations of frequency singularities in the nutation phase spectrum for nuclei of spin I=3/2 in powder substances is proposed.