Measurement of dipolar structure of O-17 nuclear quadrupole resonance lines by three-frequency irradiation

作者：Seliger J^*; Zagar V

来源：Journal of Magnetic Resonance, 2010, 203(2): 220-225.

DOI：10.1016/j.jmr.2009.12.022

• O-17
• Quadrupole resonance
• Double resonance
• Dipolar interaction

A modification of nuclear quadrupole double resonance with coupled multiplet is proposed which can be used for the measurement of the dipolar structure of the O-17 nuclear quadrupole resonance lines in case of a strong H-1-O-17 dipolar interaction. The technique is based on magnetic field cycling between a high magnetic field and zero magnetic field and on the simultaneous application of three rf magnetic fields with the frequencies that are close to the three O-17 NQR frequencies nu(5/2-1/2) > nu(5/2-3/2) >= nu(3/2-1/2) during the time spent in zero static magnetic field. When the sum of the two lower irradiation frequencies nu(1) + nu(2) is not equal to the highest irradiation frequency nu, the three-frequency irradiation increases the proton relaxation rate in zero magnetic field and consequently decreases the proton NMR signal at the end of the magnetic field cycle. The new technique is theoretically analyzed and compared to the single-frequency and two-frequency irradiation techniques. It is shown that the sensitivity of the new technique exceeds the sensitivity of the two-frequency irradiation technique. As a test of the new technique we measured the shape of the highest-frequency O-17 NQR line in paraelectric KH2PO4.

• 出版日期2010-4