Two-Frequency Nuclear Quadrupole Resonance for Line Identification

Two possible modifications of two-frequency N-14 nuclear quadrupole resonance (NQR) technique for the identification of resonance lines in NQR spectra have been studied and compared. The first one is the use of a single coil for two close frequencies (in our case, nu (+) and nu (-) lines), while the second one utilizes two coils for two different resonance frequencies. Both two-frequency methods have been applied to the carbamazepine which is a substance with a low asymmetry parameter eta of the electric field gradient tensor in crystal. It has been shown that both approaches can be applied for the identification of the N-14 NQR lines.