scholarly journals Dynamics of Interlayer Cations in Tetramethylammonium-Saponite Studied by 1H, 2H NMR, and Electrical Conductivity Measurements

1998 ◽  
Vol 53 (10-11) ◽  
pp. 903-908
Author(s):  
Shin’ichi Ishimaru ◽  
Miho Yamauchi ◽  
Ryuichi Ikeda
Keyword(s):  
Electrical Conductivity ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Conductivity Measurements ◽  
Weakly Bound ◽  
Self Diffusion ◽  
Spin Lattice ◽  
H Nmr ◽  
Water Saturated

Abstract We observed 1H and 2H NMR spectra, 1H NMR spin-lattice relaxation times, and electrical con-ductivities of water-saturated and anhydrous tetramethylammonium(TMA)-saponites between 100 and 415 K. The very weakly bound cations produced narrow 1H and 2H NMR lines observed in both specimens down to 150 K. The temperature dependence of the 'H NMR spin-lattice relaxation times in the water-saturated and anhydrous samples gave asymmetric minima attributable to the heteroge-neous overall rotation and self-diffusion of the cations. The inhomogeneity of the cationic motions in the anhydrous TMA-saponite was greater than in the water-saturated one. From measurements of the electrical conductivity of anhydrous TMA-saponite a large anisotropic cation-diffusivity was concluded.

Self-Diffusion in the Ionic Plastic Phase of (CH3 )3 NHClO4 Studied by 1H NMR and Electrical Conductivity

1996 ◽  
Vol 51 (1-2) ◽  
pp. 83-86
Author(s):  
Hiroyuki Ishida ◽  
Yoshihiro Furukawa
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Spin Relaxation ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Self Diffusion ◽  
Spin Lattice ◽  
H Nmr ◽  
Plastic Phase

Abstract Spin-lattice relaxation times (T1) and spin-spin relaxation times (T2) of 1H NMR and the electrical conductivity (σ) of trimethylammonium perchlorate were measured in the ionic plastic phase obtainable above 480 K. In this phase, both the cation and anion were revealed to perform self-diffusion. The activation energy (Ea ) of the cationic diffusion was evaluated to be 55 ± 4 and 50 ± 4 kJ mol-1 from 1H T1 and 1H T2 respectively, while Ea of the anionic diffusion was 64 ±3 kJ mol-1 from the electrical conductivity.

Bonded Hydrogen and Trapped H2 in a-Si1−xGex:H Alloys

1989 ◽  
Vol 149 ◽  
Author(s):  
E. J. Vanderheiden ◽  
G. A. Williams ◽  
P. C. Taylor ◽  
F. Finger ◽  
W. Fuhs
Keyword(s):  
Temperature Dependence ◽  
Molecular Hydrogen ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
H Nmr ◽  
Local Environments

ABSTRACT1H NMR has been employed to study the local environments of bonded hydrogen and trapped molecular hydrogen (H2) in a series of a-Si1−xGex:H alloys. There is a monotonic decrease of bonded hydrogen with increasing x from ≈ 10 at. % at x = 0 (a-Si:H) to ≈ 1 at. % at x = 1 (a-Ge:H). The amplitude of the broad 1H NMR line, which is attributed to clustered bonded hydrogen, decreases continuously across the system. The amplitude of the narrow 1H NMR line, which is attributed to bonded hydrogen essentially randomly distributed in the films, decreases as x increases from 0 to ≈ 0.2. From x = 0.2 to x ≈ 0.6 the amplitude of the narrow 1H NMR line is essentially constant, and for x ≥ 0.6 the amplitude decreases once again. The existence of trapped H2 molecules is inferred indirectly by their influence on the temperature dependence of the spin-lattice relaxation times, T1. Through T1, measurements it is determined that the trapped H2 concentration drops precipitously between x = 0.1 and x = 0.2, but is fairly constant for 0.2 ≤ x ≤ 0.6. For a-Si:H (x = 0) the H2 concentration is ≈ 0.1 at. %, while for x ≥ 0.2 the concentration of H2 is ≤ 0.02 at. %.

Water-Saturated Mesoporous MCM-41 Systems Characterized by 1H NMR Spin-Lattice Relaxation Times

1995 ◽  
Vol 99 (12) ◽  
pp. 4148-4154 ◽  
Author(s):  
Eddy Walther Hansen ◽  
Ralf Schmidt ◽  
Michael Stoecker ◽  
Duncan Akporiaye
Keyword(s):  
1H Nmr ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Water Saturated ◽  
Mcm 41

Nuclear magnetic resonance spin–lattice relaxation and the rotation of adamantane and hexamethylenetetramine in solution

1977 ◽  
Vol 55 (13) ◽  
pp. 2564-2569 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Brian A. Pettitt
Keyword(s):  
Variable Temperature ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Hard Sphere Model ◽  
Correlation Times ◽  
Spin Lattice ◽  
H Nmr ◽  
Large Step ◽  
Resonance Spin

Deuterium nmr spin–lattice relaxation times have been measured for dilute solutions of adamantane-d16 in CH2I2, CHBr3, CCl4, CHCl3, and CH2Cl2. The reorientation correlation times, τ2, calculated from the experimental data are used to calculate τJ, the angular momentum correlation times, assuming both the J-diffusion and Hubbard relations. The derived τJ values suggest that adamantane executes small step diffusion in CH2I2 and CHBr3, and large step diffusion in CCl4, CHCl3, and CH2Cl2. The calculated τJ values do not appear to be related to the mean times between collisions calculated using a hard sphere model. Both variable solvent and variable temperature experiments indicate 1 ps/cP for the viscosity dependence of the adamantane reorientation time, about 1/36th the value predicted using the familiar Stokes–Einstein equation.Carbon-13 and 1H nmr T1 data indicate that reorientation of hexamethylenetetramine in H2O (28 ps/cP), CHCl3 (27 ps/cP), and CHBr3 (18 ps/cP) is severely hindered because of inter-molecular hydrogen bonding.

scholarly journals 15N and 133Cs Solid NMR Studies on Ionic Dynamics in Plastic CsNO2

1996 ◽  
Vol 51 (5-6) ◽  
pp. 761-768 ◽  
Author(s):  
H. Honda ◽  
M. Kenmotsu ◽  
N. Onoda-Yamamuro ◽  
H. Ohki ◽  
S. Ishimaru ◽  
...  
Keyword(s):  
Phase Ii ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Temperature Phase ◽  
Nmr Studies ◽  
Self Diffusion ◽  
Spin Lattice ◽  
Solid Nmr ◽  
Plastic Phase

The temperature dependence of the 15N and 133Cs NMR spin-lattice relaxation times, the 15N spin-spin relaxation time, and the 15N and 133Cs spectra of CsNO2 was observed in the plastic phase (209.2 < T < 673 K (m. p.)) and the low-temperature phase (Phase II). In Phase II we found the NO-2 180°-flip, which could be attributed to the anomalous increase of the heat capacity curve, and determined the activation energy of this motion to be 8.7-11.7 kJ mol-1. The 15N and 133Cs spectra in this phase are inconsistent with the reported crystal structure R3̅m and can be explained by lower crystal symmetry. In the plastic phase we detected a new anionic motion with 11 kJ mol-1 , an isotropic NO-2 reorientation with 8.5-9 kJ mol-1, and ionic self-diffusion with 47 kJ mol-1. The presence of ionic self-diffusion was confirmed by measuring the electrical conductivity.

Molecular Motions in Halogen-Bridged One-Dimensional Pt Complexes, [PtII(en)2][PtIVX2(en)2](ClO4)4 (X = Cl, Br) Studied by 2H and 1H NMR

2002 ◽  
Vol 57 (6-7) ◽  
pp. 413-418 ◽  
Author(s):  
Noriyoshi Kimura ◽  
Toru Hachisuka ◽  
Yukitaka Nakano ◽  
Ryuichi Ikeda
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Energy Difference ◽  
Spin Lattice Relaxation ◽  
X Ray Diffraction ◽  
Potential Wells ◽  
One Dimensional ◽  
X Ray ◽  
Spin Lattice ◽  
H Nmr

2H and 1H NMR measurements were performed on crystalline [Pt(en)2][PtX2(en)2](ClO4)4 (X = Cl, Br), where the protonated and partially deuterated ethylenediamines (en’s), NH2(CH2)2NH2, NH2(CD2)2NH2 and ND2(CH2)2ND2 were used as ligands. Measurements of 2H and 1H NMR spin-lattice relaxation times showed the presence of motions of en chelate rings at the temperatures near the phase transitions, whereas broad 2H NMR spectra and the reported X-ray diffraction data showed no marked motions. These results were consistently explained by introducing the en puckering motion between highly asymmetric potential wells with an energy difference of 10 - 13 kJ mol-1. This difference was shown to be much larger than 2 - 5 kJ mol-1, reported for the iodo-complex, [Pt(en)2][PtI2(en)2](ClO4)4

H NMR Study of Ionic Motions in High Temperature Solid Phases of (CH3NH3)2ZnCl4

2000 ◽  
Vol 55 (3-4) ◽  
pp. 412-414 ◽  
Author(s):  
Hiroyuki Ishida
Keyword(s):  
Activation Energy ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
The Self ◽  
Spin Lattice Relaxation ◽  
Temperature Phase ◽  
Self Diffusion ◽  
Spin Lattice ◽  
H Nmr ◽  
Nmr Study

Abstract The reorientation of the tetrahedral complex anion ZnCl42- and the self-diffusion of the cation in (CH3NH3)2ZnCl4 were studied by 1H NMR spin-lattice relaxation time (1H T1) experiments. In the second highest-temperature phase, the temperature dependence of 1H T1 observed at 8.5 MHz could be explained by a magnetic dipolar-electric quadrupolar cross relaxation between 1H and chlorine nuclei, and the activation energy of the anion motion was determined to be 105 kJ mol -1 . In the highest-temperature phase, the activation energy of the self-diffusion of the cation was determined to be 58 kJ mol -1 from the temperature and frequency dependence of 1H T1

Ionic Dynamics in LiNO2 Studied by 7Li and 15N Solid NMR

1999 ◽  
Vol 54 (8-9) ◽  
pp. 519-523 ◽  
Author(s):  
Hisashi Honda ◽  
Shin'ich Ishimaru ◽  
Ryuichi Ikeda
Keyword(s):  
Relaxation Times ◽  
Activation Parameters ◽  
Lattice Relaxation ◽  
The Self ◽  
Spin Lattice Relaxation ◽  
Plastic Crystal ◽  
Self Diffusion ◽  
Spin Lattice ◽  
Solid Nmr ◽  
Temperature Dependences

The temperature dependences of 7Li and 15N NMR spin-lattice relaxation times and spectra in LiNO2 were measured in the range 120 K -473 K (m.p.). The 180°-flip motion of NO2-- ions along or perpendicular to the molecular C2 -axis and the self-diffusion of Li+ ions (activation energies of 42 -44 and 100 kJ mol-1 , respectively) were observed in this range. From the comparison of the observed activation parameters with those reported for plastic phases of alkali metal nitrites, a new characteristic of the plastic crystal was obtained.

Self-Diffusion and Reorientation of Methylammonium Ions in (CH3NH3)2ZnCl4 Crystals as Studied by 1H-NMR

1989 ◽  
Vol 44 (8) ◽  
pp. 741-746 ◽  
Author(s):  
Hiroyuki Ishida ◽  
Tadashi Iwachido ◽  
Naomi Hayama ◽  
Ryuichi Ikeda ◽  
Mifune Terashima ◽  
...  
Keyword(s):  
Solid Phase ◽  
Relaxation Times ◽  
Three Dimensional ◽  
Lattice Relaxation ◽  
High Temperature Phase ◽  
Spin Lattice Relaxation ◽  
Temperature Phase ◽  
Scanning Calorimetry ◽  
Self Diffusion ◽  
H Nmr

Abstract Differential thermal analysis, differential scanning calorimetry, and measurements of the 1H spin-lattice relaxation times and second moments of 1H-NMR absorptions were performed on methylammonium tetrachlorozincate (II) crystals over a wide temperature range. A solid-solid phase transition was located at 477 K. From the 1H-NMR experiments it was found that the cations undergo overall reorientation as well as three dimensional translational self-diffusion in the high-temperature phase. In the low-temperature phase, a 120° reorientational motion of the CH3 and NH3+ groups of the cation about its C-N bond axis was detected. The parameters for the motional modes of the cations in the crystal were evaluated from the analysis of the 1H-NMR experimental results.

Deuteron Magnetic Resonance in a-Si and a-SiGe Produced from Fluorides

1986 ◽  
Vol 70 ◽  
Author(s):  
V. P. Bork ◽  
P. A. Fedders ◽  
R. E. Norberg ◽  
D. J. Leopold ◽  
K. D. Mackenzie ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Resonance Line ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Weakly Bound ◽  
Spin Lattice ◽  
Line Shapes ◽  
Quadrupolar Doublet

ABSTRACTDeuteron magnetic resonance line shapes and spin lattice relaxation times are presented for a-Si:D, F and a-SiGe:D, F. These parameters differ from those for typical a-Si:D, H samples, but in some respects are similar to those for an annealed a-Si:D, H sample. The a-SiGe:D, F spectra display an unusually large broad central weakly bound D resonance component and a barely-resolved Ge-D quadrupolar doublet. Comparisons indicate substantial differences in void morphology between the a-Si:D, F and a-SiGe:D, F.

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