Intermolecular Zero-Quantum Coherences of Multi-component Spin Systems in Solution NMR

Intermolecular zero-quantum coherences (iZQC) induced by the dipolar demagnetizing field can give both P- and N-type cross peaks. This paper shows that the relative intensities of the two types of iZQC peaks follow a simple relation, tan² (θ/2), from both the quantum (spin density matrix) and classical (modified Bloch equation) calculations. The experimental data and numerical simulations agree well with the prediction. In addition, higher-order iZQCs are experimentally examined for the first time and are explained by the quantum picture in which dipolar couplings convert four-spin operators into observable magnetization. © 1998 Academic Press.

Duke Scholars

Author Warren S. Warren Chemistry