Heteronuclear double resonance on formamide-¹⁵N and ammonium-¹⁵N using weak perturbing radiofrequency fields

Abstract

Weak radiofrequency fields have been used to perturb nitrogen transitions in the formamide-15N and ammonium-15N molecules. Observation of the proton spectra has completed the determination of the relative signs of the coupling constants in formamide-15N. Chemical shifts precisely related to tetramethylsilane are reported and a discussion of a method for presentation of shift results is included.