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Nuclear spin relaxation rates of (2) H and (139) La in LaCl3 +(2) H2 O and La(ClO4 )3 +(2) H2 O solutions were determined as a function of pressure in order to demonstrate a new NMR probe designed for solution spectroscopy at geochemical pressures. The (2) H longitudinal relaxation rates (T1 ) vary linearly to 1.6 GPa, consistent with previous work at lower pressures. The (139) La T1 values vary both with solution chemistry and pressure, but converge with pressure, suggesting that the combined effects of increased viscosity and enhanced rates of ligand exchange control relaxation. This simple NMR probe design allows experiments on aqueous solutions to pressures corresponding roughly to those at the base of the Earth's continental crust.

Nuclear spin relaxation rates of (2) H and (139) La in LaCl3 +(2) H2 O and La(ClO4 )3 +(2) H2 O solutions were determined as a function of pressure in order to demonstrate a new NMR probe designed for solution spectroscopy at geochemical pressures. The (2) H longitudinal relaxation rates (T1 ) vary linearly to 1.6 GPa, consistent with previous work at lower pressures. The (139) La T1 values vary both with solution chemistry and pressure, but converge with pressure, suggesting that the combined effects of increased viscosity and enhanced rates of ligand exchange control relaxation. This simple NMR probe design allows experiments on aqueous solutions to pressures corresponding roughly to those at the base of the Earth's continental crust.

Nuclear spin relaxation rates of 2H and 139La in LaCl3+2H2O and La(ClO4)3+2H2O solutions were determined as a function of pressure in order to demonstrate a new NMR probe designed for solution spectroscopy at geochemical pressures. The 2H longitudinal relaxation rates (T1) vary linearly to 1.6 GPa, consistent with previous work at lower pressures. The 139La T1 values vary both with solution chemistry and pressure, but converge with pressure, suggesting that the combined effects of increased viscosity and enhanced rates of ligand exchange control relaxation. This simple NMR probe design allows experiments on aqueous solutions to pressures corresponding roughly to those at the base of the Earth's continental crust. [ABSTRACT FROM AUTHOR]

A correction to the article "²H and 139La NMR Spectroscopy in Aqueous Solutions at Geochemical Pressures" that was published in the 2015 issue is presented.

Nuclear-magnetic resonance (NMR) spectra of CsCl and LaCl 3 in D 2 O/H 2 O solutions were collected up to pressures of 1.9 GPa using a new NMR probe design that considerably extends the pressure range available for geochemical experiments. The longitudinal-relaxation times ( T 1 ) for 2 H compare well with those reported in the previous studies of Lee et al. (1974), who examined lower pressures, and indicate that the probe functions properly. In some experiments, 133 Cs and 1 H NMR spectra could be taken on solutions to pressures well beyond the nominal freezing pressure of D 2 O or H 2 O to form Ice VI (near 0.9 GPa). Freezing to form the high-pressure ice is kinetically slow on an experimental time scale (minutes to hours). The data indicate that the electrolyte concentrations increase the freezing pressure of the solution. This result means that solution NMR spectra can be collected at pressures that are nearly twice the nominal freezing pressure of pure D 2 O or H 2 O. Pulsed-magnetic-field-gradient NMR methods are used to independently measure the self-diffusion coefficient of H 2 O in these solutions, which yields estimates of solution viscosity via the Stokes–Einstein relation. The increased viscosity accounts for the pressure variation of T 1 values as rates of molecular tumbling are affected. Accounting for such changes is essential if NMR spectral line widths are used to infer pressure-enhanced rates of geochemical reactions, such as interconversion of aqueous complexes. [ABSTRACT FROM AUTHOR]