Proton NMR relaxation in hydrous melts

Conference · Thu Jan 01 04:00:00 EST 1976

OSTI ID:7347849

Braunstein, J; Bacarella, A L; Benjamin, B M; Brown, L L; Girard, C

Pulse and continuous wave NMR measurements are reported for protons in hydrous melts of calcium nitrate at temperatures between -4 and 120/sup 0/C. Although measured in different temperature ranges, spin-lattice (T/sub 1/) and spin-spin (T/sub 2/) relaxation times appear to be nearly equal to each other and proportional to the self-diffusion coefficients of solute metal cations such as Cd/sup 2 +/. At temperatures near 50/sup 0/C, mean Arrhenius coefficients ..delta.. H/sub T/sub 1// (kcal/mol) are 7.9, 7.3, and 4.8, respectively, for melts containing 2.8, 4.0, and 8.0 moles of water per mole of calcium nitrate, compared to 4.6 kcal/mol for pure water. Temperature dependence of T/sub 1/ and T/sub 2/ in Ca(NO/sub 3/)/sub 2/-2.8 H/sub 2/O between -4 and 120/sup 0/C are non-Arrhenius and can be represented by a Fulcher-type equation with a ''zero mobility temperature'' (T/sub 0/) of 225/sup 0/K, close to the value of T/sub 0/ for solute diffusion, electrical conductance and viscosity. Resolution of the relaxation rates into correlation times for intramolecular (rotational) and intermolecular (translational) diffusional motion is discussed in terms of the Bloembergen-Purcell-Pound and more recent models for dipolar relaxation. (auth)

• Research Organization: Oak Ridge National Lab., Tenn. (USA)
• OSTI ID: 7347849
• Report Number(s): CONF-760521-2
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
BARYONS
CALCIUM COMPOUNDS
CALCIUM NITRATES
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HYDRATION
MAGNETIC RESONANCE
MOLTEN SALTS
NITRATES
NITROGEN COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
OXYGEN COMPOUNDS
PROTONS
RELAXATION
RESONANCE
SALTS
SOLVATION
SPIN-LATTICE RELAXATION
SPIN-SPIN RELAXATION
TEMPERATURE DEPENDENCE