Excitation of quadrupole spin echoes

Abstract

Quadrupole spin echoes excited by a train of pulses with differing radio-frequency carriers, the carrier frequencies being ω_Q and ω_Q ± Δω_Q, where ω_Q is the resonance frequency of the excited transition and Δω_Q is a frequency detuning less than half the linewidth of nuclear quadrupole resonance, are studied for the first time. It is shown that, in this case, the amplitudes of detected echo signals are independent of the detuning and that the positions of these signals on the time axis depends on the time intervals between the excitation pulses, on Δω_Q/ω_Q, and on the sign of the detuning.