Multiple Refocusing in NMR Spectroscopy: Compensation of Pulse Imperfections by Scalar Couplings

✍ Scribed by Jens Dittmer; Geoffrey Bodenhausen

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 254 KB
• Volume: 5
• Category: Article
• ISSN: 1439-4235
• DOI: 10.1002/cphc.200400073

✦ Synopsis

Abstract

__When applying multiple refocusing pulses to characterize the cross‐correlated relaxation of heteronuclear multiple quantum coherence 2__N~x~H~x~ in biomolecules, the unavoidable effects of pulse imperfections are compensated by the scalar couplings between nitrogen atoms and protons. The experiment, which is useful as a tool for studying slow internal dynamics of biomolecules, greatly benefits from this compensation. The underlying effect is a manifestation of an interchange between three noncommuting components of the density operator. One perturbing Hamiltonian is counteracted by another, which leads to a nearly complete suppression of the perturbation. The effect proves to be an example of a hitherto unknown phenomenon in NMR spectroscopy.