NQR and NMR methods allow for the investigation of incommensurately modulated structure because the resonance frequencies change in space in such a way that they reflect the variation of the incommensurate (I) modulation. Much work has been carried out on the steady state of these systems, but dynamical studies are limited [1, 2]. The NQR spinlattice relaxation time Tj has been studied by us an...

Z. Naturforsch. 45a, 353-356 (1990); received August 25, 1989 The 1 N nuclear quadrupole resonance (NQR) of the cyanides in Ba[Fe(CN)sNO] • 3 H 2 0 (BNP) was observed between 77 and 293 K. Phase transitions exist at 118,131 (both weakly first order) and 233 K (second order). Most of the cyanides were perturbed by the structural changes except for one of the trans cyanides that was only affected...

The C1 NQR frequencies in MgTeCl6 • 6 H 2 0 , NiTeCl6 • 6 H 2 0 , and NiIrCl6 • 6 H 2 0 have been determined at various temperatures. These compounds form rhombohedral crystals with the space group R3, showing a single resonance line. The C1 NQR frequencies of the Te(IV) complexes exhibit an unusual positive temperature coefficient. The deuterated analogs of the Te(IV) complexes show a small fr...

The Na(+)-pumping NADH:quinone oxidoreductase (Na(+)-NQR) is the main entrance for electrons into the respiratory chain of many marine and pathogenic bacteria. The enzyme accepts electrons from NADH and donates them to ubiquinone, and the free energy released by this redox reaction is used to create an electrochemical gradient of sodium across the cell membrane. Here we report the role of glyci...

The 35C1 NQR spectra of 2,4,4,6-tetrachloro-3,5-dimethyl-cyclohexadiene-2,5-one-l and 2,4,4,6tetrachloro-cyclohexadiene-2,5-one-l were studied from 77 K up to the decomposition temperature, their crystal structure having been determined by single crystal X-ray diffraction. The first com­ pound crystallizes in the monoclinic space group C2h-P2!/m with two molecules in the unit cell. The lattice ...

The 14N NQR from the host lattice of the thiourea-carbon tetrachloride inclusion compound. From calorimetric measurements, two phase transitions are known to occur at 67.2 K and 41.3 K in this compound. Above the 67.2 K transition, the 14N NQR spectrum consists of one resonance, though a small splitting of about 0.5 kHz is seen at temperatures up to ca. 105 K. Below the transition, the resonanc...

The influence of impurities on the N NQR lineshape of Na1_^AgcN02 and [NaN02],_,[BN03]^ (B = Na, K) at room temperature has been investigated. Carrying out spectral analysis in conjunction with classification of the local field inhomogeneities according to the structurally isomorphic, Na]_xAgxN02, and anisomorphic [NaNO^.JBNC^b systems, enabled an understanding of the microscopic nature of impu...

NQR of Cu in YBa2Cu3O ö 95 was investigated before and after low-temperature electron irradi­ ation as well as after annealing at several distinct temperatures up to 440 K. Irradiation with 2.76 MeV electrons (fluence (f)t = 2.2 ■ 1023 e_/m2) decreased the critical temperature Tc from 91.8 K to 89.5 K. The NQR spectra indicate that the e~ irradiation displaces so-called 0(4) atoms in the Cu-O c...

Fifteen methyl-, nitro-, or mixed substituted N-(phenyl)-2-chloroacetamides were investigated by C1 NQR. The temperature dependence of the frequencies of the 3-methylphenyl and 2,6-dimethylphenyl derivatives were studied for the range 77 K<T<300 K. Only one co C-Cl frequency was observed for the compound with the two exceptions. For N-(2-nitro,4-chlorophenyl)-2-chloroacetamide the observed valu...