Nuclear quadrupole double resonance

Quadrupole coupling constants, χQ, for the deuteron and the oxygen nuclei in neat, liquid water were determined by both theoretical and experimental methods. The theoretical values of χD=264 kHz and χO=8.4 MHz obtained from ab initio calculations at the MP2/6‐31+G* level in combination with a quantum cluster equilibrium model for liquids are in good agreement with results from NMR relaxation time experiments. Both theory and experiment show no observable temperature dependence of the quadrupole coupling constants. The theoretical values reported here for the oxygen quadrupole coupling constant and both the oxygen and deuterium asymmetry parameters are different from values obtained from ab initio calculations of clusters using molecular dynamics methods. This may be due to the use of pairwise additive potentials in the molecular dynamics simulations which do not take into account many‐body or polarizability effects.

Experimental and theoretical determination of the temperature dependence of deuteron and oxygen quadrupole coupling constants of liquid water

Solid-state 17O NMR studies of organic and biological molecules

Analysis of the 1H-17O dipolar contribution to the proton longitudinal relaxation rate in 17O-enriched water yields a correlation time for re-orientation of the O–H vector τrOH = (1.71 ± 0.07) ps in H2O at 25 °C. This result is insensitive to uncertainties in the calculated intermolecular relaxation contribution. From 1H, D, and 17O relaxation rates in H2O/D2O mixtures deuterium isotope effects on the correlation times were estimated. The quadrupole coupling constants of D and 17O in liquid water were determined.

W.F Sherman

Papers

The nuclear quadrupole resonance of 2D and 17O in Ice II

Nuclear quadrupole resonance of 2D and 17O in ices V, VI, VIII, and IX