title: Heteronuclear J-coupling measurements in grossly inhomogeneous magnetic fields.
abstract: It is difficult to measure chemical shifts in the small and inhomogeneous magnetic fields found in ex situ and single-sided NMR systems, such as those used for well-logging. However, it is still possible to obtain chemical information from J-coupling constants, which are independent of static field strength and temperature. We describe and analyze (1)H-(13)C double-resonance pulse sequences that are suitable for measuring heteronuclear J-coupling in grossly inhomogeneous fields. We also present preliminary experimental results from a low-frequency fringe-field system.
authors.affiliation: Case Western Reserve University, Cleveland, OH 44106, USA; Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: sxm833@case.edu.
authors.forename: S
authors.initials: S
authors.lastname: Mandal
authors.affiliation: Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: ysong@slb.com.
authors.forename: Y-Q
authors.initials: YQ
authors.lastname: Song
keywords: Inhomogeneous fields; J-coupling; Ultra-broadband electronics