Frequency- and phase-modulated heteronuclear decoupling in rotating solids

✍ Scribed by Zhehong Gan; R.R. Ernst

• Book ID: 104357833
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 91 KB
• Volume: 8
• Category: Article
• ISSN: 0926-2040
• DOI: 10.1016/s0926-2040(96)01294-5

✦ Synopsis

The mechanism of heteronuclear dipolar decoupling by the TPPM sequences, proposed by Bennett et al. (J. Chem. Phys. 103 (1995) 6951) is investigated by comparison with a modified pulse sequence, called TPFM, that uses frequency instead of phase modulation. By combining frequency and phase modulations, circularly modulated sequences are designed. The fact that only the left-handed modulation sequence FMPML leads to improved proton decoupling, while the right-handed modulation sequence FMPMR is ineffective, proves that the efficient decoupling is caused by a secondary resonance effect.