Studies have been carried out of effects of 17O substitution on a Mo(V) e.p.r. signal from xanthine oxidase, known as Very Rapid. This transient signal is believed to represent an intermediate in enzymic turnover. When Very Rapid was developed from enzyme equilibrate with 17O-enriched water, strong coupling of Mo(V) to a single oxygen atom was observed, with A(17O)1,2,3 1.34, 1.40, 1.36 mT. The...

The quadrupole coupling constants in solids usually depend on temperature (see f.e. Ref. [1 — 8 ]). This can be explained by the change of vibration amplitudes of molecules, but the influence of the volume expansion on the electric field gradient has also to be taken into account [4], For 185Re and 187Re in some peirhenates NQR measurements have been reported [9 — 16]. With the exception of NH ...

A novel diode laser spectrometer was developed using dualwavelength multiplexing, ensuring ideal conditions for high-precision and simultaneous measurements of the 2H/1H, 17O/16O, and 18O/16O isotope ratios in water. A 1.4-m diode laser probed a H16OH / HO2H line pair near 7198 cm-1, while a similar laser observed H16OH, H17OH, and H18OH rovibrational lines around 7183 cm-1, or a H16OH / H18OH ...

The DFS enhancement method as applied to 17O MAS NMR was critically assessed, first on NaPO3, a simple binary glass system, and in a second step, on a series of catalysis-related organometallic molecules and materials. The robustness of DFS was investigated for the wide range of anisotropic parameters (quadrupolar coupling and chemical shift anisotropy) encountered in these samples. Emphasis ha...

We investigated microscopic lattice states in the donor-acceptor ionic Mott insulator, tetrathiafulvalene-bromanil (TTF-BA), by $^{79}\mathrm{Br}\text{\ensuremath{-}}$nuclear quadrupole resonance (NQR) spectroscopy to explore cross-correlated fluctuations between spin, charge, and lattice. A ferroelectric transition with dimerization is captured a NQR line splitting critical exponent $\ensurema...