Bräuniger Thomas, Madhu P K
Institute of Physics, University of Halle, Friedemann-Bach-Platz 6, DE-06108 Halle, Germany.
J Magn Reson. 2008 Jul;193(1):102-9. doi: 10.1016/j.jmr.2008.04.027. Epub 2008 Apr 20.
We here investigate the sensitivity enhancement of central-transition NMR spectra of quadrupolar nuclei with spin-7/2 in the solid state, generated by fast amplitude-modulated RF pulse trains with constant (FAM-I) and incremented pulse durations (SW-FAM). Considerable intensity is gained for the central-transition resonance of single-quantum spectra by means of spin population transfer from the satellite transitions, both under static and magic-angle-spinning (MAS) conditions. It is also shown that incorporation of a SW-FAM train into the excitation part of a 7QMAS sequence improves the efficiency of 7Q coherence generation, resulting in improved signal-to-noise ratio. The application of FAM-type pulse trains may thus facilitate faster spectra acquisition of spin-7/2 systems.
我们在此研究固态中自旋为7/2的四极核的中心跃迁核磁共振谱的灵敏度增强，这是由具有恒定脉冲持续时间的快速幅度调制射频脉冲序列（FAM-I）和递增脉冲持续时间的序列（SW-FAM）产生的。在静态和魔角旋转（MAS）条件下，通过卫星跃迁的自旋布居转移，单量子谱的中心跃迁共振获得了相当大的强度。还表明，将SW-FAM序列纳入7QMAS序列的激发部分可提高7Q相干产生的效率，从而提高信噪比。因此，FAM型脉冲序列的应用可能有助于更快地采集自旋为7/2系统的谱图。
