The method of random sampling was introduced for the first time in the nutation nuclear quadrupole resonance (NQR) spectroscopy where the nutation spectra show characteristic singularities in the form of shoulders. The analytic formulae for complex two-dimensional (2-D) nutation NQR spectra (I = 3/2) were obtained and the condition for resolving the spectral singularities for small values of an...

Some nitrogen-containing heterocycles can form both anionic (with abstraction of the N -H proton) and cationic derivatives (with addition of the proton to the pyridinic nitrogen atom). These include, in par­ ticular, 3,5-dichloro-l,2,4-triazole and 4,5-dichloro-2methylimidazole. These compounds were studied by 35C1 NQR spectroscopy [1,2]. Quantum-chemical analyses of the electronic structure of...

Zero field NMR and NQR spectra are obtained by the application of dc magnetic field pulses to a demagnetized sample. Pulsed dc fields allow for selective excitation of isotopic species and provide a means for coherent manipulation of the spin system in zero field. Using these selective pulses and level crossing techniques, indirect detection of a quadrupolar nucleus may be accomplished via prot...

For Y B a 2 C u 3 0 7 _ a powder samples of different average grain sizes the temperature dependences of 6 Cu NQR frequencies and signal intensities are reported for the Cu (1) site in a temperature range of 4 300 K. Both quantities show a non-monotonic behaviour in the vicinity of the superconduction transition temperature Tc. In the superconducting state the line shape of the NQR signal in ze...

The 35C1-NQR spectrum of several derivatives of chloral, Cl3CCHO, was studied in the ranee 77 K ^ T Tm. By use of the spin echo double resonance technique a relative assignment of the resonances to different ClaC-groups within one crystallized compound was possible. The solid compounds studied are: High temperature phase of chloral hydrate, Cl3CCH(OH)2; parachloral, (Cl3CCHO)3, (aand ß-isomer);...

63-65Cu and 79,81Br spectra of halogenocuprate (I) complexes containing [CuPPh3 X2]~ (X = C1, Br, I) anions with different cations were recorded in the range 77 K -300 K. The results confirm the previous trend that, for a given ligand, 63Cu NQR frequencies are in the order C l> B r> I. fe3Cu NQR frequencies in [CuPPh3 X2]_ are compared with those in neutral Cu(Ph3 )2 X(X = Cl, Br) complexes and...

mp2 calculations with cc-pvtz basis set were used to analyze intermolecular interactions in f3cx···yli···nccn and f3cx···nccn···liy triads (x = cl, br; y = cn, nc) which are connected via halogen and lithium bonds. those complexes with the role of liy as halogen acceptor and lithium donor show cooperativity with energy values ranging between -1.97 and -2.92 kj mol-1. those complexes with simult...

We report a study of the Mott insulator ${\mathrm{La}}_{2}{\mathrm{O}}_{3}{\mathrm{Fe}}_{2}{\mathrm{Se}}_{2}$ by means $^{139}\mathrm{La}$ nuclear quadrupole resonance (NQR). The NQR spectra evidence single La site in paramagnetic phase and two inequivalent sites, La1 La2, antiferromagnetic phase. These sites are characterized different couplings, indicative distinct lattice configurations segr...

Li3InBr6 and NaInBr4 have been synthesized and characterized by means of DTA, 8 'Br NQR, Li, Li, Na, and l l In NMR, and AC conductivity. These measurements revealed the presence of phase transitions and cationic diffusion in both compounds. From the spin-lattice relaxation times of 1 Br NQR and the peak widths of Li and Na NMR spectra, it is deduced that the conduction is due to cationic diffu...