23Na Spin-Lattice Relaxation Measurements in Dehydrated Na-X Zeolite

1996 ◽  
Vol 51 (5-6) ◽  
pp. 657-661 ◽  
Author(s):  
Mutsuo Igarashi ◽  
Noriaki Okubo ◽  
Shuichi Hashimoto ◽  
Deok Joon Cha ◽  
Ryozo Yoshizaki
Keyword(s):  
Relaxation Time ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Raman Process ◽  
Relaxation Measurements ◽  
X Zeolite ◽  
Single Exponential

Abstract The spin-lattice relaxation time T1 of 23Na-NMR in a dehydrated Na-X zeolite has been measured from 20 to 300 K. The recovery curve is not single-exponential at all measured temperatures and T1-1 increases with the square of temperature around room temperature. The results are analyzed by assuming non-equivalent sites and by applying the theory of the Raman process based on covalency.

scholarly journals 23Na Nuclear Spin-Lattice Relaxation in Dehydrated Zeolite NaY

1998 ◽  
Vol 53 (6-7) ◽  
pp. 442-446
Author(s):  
Mutsuo Igarashi ◽  
Noriaki Okubob ◽  
Ryozo Yoshizaki
Keyword(s):  
Relaxation Time ◽  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Zeolite Nay ◽  
Spin Lattice ◽  
Raman Process ◽  
Nuclear Spin Lattice Relaxation ◽  
Single Exponential

Abstract The spin-lattice relaxation time T1 of 23Na-NMR in dehydrated zeolite NaY has been measured from 26 to 300 K. The magnetization recovery curve is not single-exponential at all measured temperatures and T1-1 increases in proportion to the square of temperature above 200 K. The result is analyzed with a theory of the Raman process based on covalency. The value of T1 is compared with that of NaX in which the concentration of Na is about 2 times larger than in NaY.

Incommensurability and Domain Structure of K2SbF5

2002 ◽  
Vol 57 (6-7) ◽  
pp. 456-460
Author(s):  
A. M. Panich ◽  
L. A. Zemnukhova ◽  
R. L. Davidovich
Keyword(s):  
Relaxation Time ◽  
Phase Transitions ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Spin Lattice ◽  
Relaxation Measurements ◽  
Increasing Temperature

Phase transitions and incommensurability in K2SbF5 have been studied by means of 123Sb NQR spectra and spin-lattice relaxation measurements. The phase transitions occur at 117, 135 and 260 K. The line shape and temperature dependence of the spin-lattice relaxation time T1 at 135 to 260 K are characteristic for an incommensurate state with a plane wave modulation regime. At 117 to 135 K a distinct fine structure of the NQR spectra has been observed. The X-ray diffraction pattern of this phase is interpreted as a coexistence of two modulation waves along the a and b axis with wave vectors (a*/6 + b*/6) and (a*/2 + b*/2), respectively. The best interpretation that fits our NQR data is a coexistence of two domains, the structures of which are modulated with different periods in such a manner that each domain exhibits only one of the aforementioned modulation waves. Redistribution of line intensities with the variation of temperature shows that one of the domains becomes energetically preferable on cooling and is transformed into the low temperature phase at 117 K. The 123SbNQR measurements in K2SbF5 show unusually short values of T1, which become close to the spin-spin relaxation time T2 with increasing temperature. - Pacs: 61.44.Fw, 64.60, 64.70, 64.70.Rh, 76.60

81Br Nuclear Quadrupole Relaxation in Aluminium Tribromide

1995 ◽  
Vol 50 (8) ◽  
pp. 737-741 ◽  
Author(s):  
Noriaki Okubo ◽  
Mutsuo Igarashi ◽  
Ryozo Yoshizaki
Keyword(s):  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Quadrupole Relaxation ◽  
Spin Lattice ◽  
Raman Process ◽  
Nuclear Spin Lattice Relaxation ◽  
Nuclear Quadrupole ◽  
Nuclear Quadrupole Relaxation

Abstract The 81Br nuclear spin-lattice relaxation time in AlBr3 has been measured between 8 K and room temperature. The result is analyzed using the theory of the Raman process based on covalency. A Debye temperature of 67.6 K and covalency of 0.070 and 0.072 for terminal and 0.022 for bridging bonds are obtained. The correspondence of the latter values to those obtained from the NQR frequencies is low, in contrast to the previously examined compounds.

An 1H NMR Study on the Cationic Motion in Solid tert-Butylammonium Chloride and Bromide

1991 ◽  
Vol 46 (3) ◽  
pp. 265-268 ◽  
Author(s):  
Hiroyuki Ishida ◽  
Syuichi Inada ◽  
Naomi Hayama ◽  
Daiyu Nakamura ◽  
Ryuichi Ikeda
Keyword(s):  
Relaxation Time ◽  
1H Nmr ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
X Ray ◽  
Spin Lattice ◽  
H Nmr ◽  
Nmr Study

AbstractThe 1H spin-lattice relaxation time (T1) in solid (CD3)3CNH3Cl and (CD3)3CNH3Br was measured above room temperature and the motional parameters for the reorientation of the NH3+ groups were determined. The 1H NMR absorptions measured in the same temperature range for (CH3)3CNH3Cl and (CH3)3CNH3Br indicate the presence of superimposed several cationic motions commonly taking place in both compounds. From X-ray powder patterns taken at room temperature, the bromide was found to be isomorphous with the chloride

scholarly journals 79Br Nuclear Quadrupole Relaxation in the High Temperature Modification of Niobium Pentabromide

1992 ◽  
Vol 47 (6) ◽  
pp. 713-720 ◽  
Author(s):  
Noriaki Okubo ◽  
Harutaka Sekiya ◽  
Chiaki Ishikawa ◽  
Yoshihito Abe
Keyword(s):  
Relaxation Time ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Quadrupole Relaxation ◽  
Spin Lattice ◽  
Raman Process ◽  
35Cl Nqr ◽  
High Temperature Modification ◽  
Nuclear Quadrupole Relaxation

AbstractThe spin-lattice relaxation time of 79Br NQR has been measured between 4.2 K and room temperature. The result is compared with that of 35Cl NQR in NbCl5. The origin of the relaxation is attributed to the quadrupolar interaction and the temperature dependence is explained by the Raman process. The Debye temperature is determined to be 94 K and the relaxation time is related with the NQR frequency through the covalency.

A Study of Complex Anionic Motions in (Me2NH2)2ZnCl4 Crystals by Means of Chlorine Nuclear Quadrupole Resonance Techniques

1990 ◽  
Vol 45 (3-4) ◽  
pp. 464-466 ◽  
Author(s):  
Hiroshi Yamamoto ◽  
Atsushi Ishikawa ◽  
Tetsuo Asaji ◽  
Daiyu Nakamura
Keyword(s):  
Phase Transition ◽  
Relaxation Time ◽  
Transition Temperature ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract Three 35Cl NQR frequencies were observed for (Me2NH2)2ZnCl4 at room temperature, indicating the existence of three crystallographically nonequivalent chlorines in the crystal. With decreasing temperature, the frequency of the lines increased almost linearly and disappeared below ca. 220 K near the reported phase transition temperature (ca. 215 K) detected on cooling. The three NQR lines faded out above room temperature because of the occurrence of rapid anionic reorientational motions disclosed from measurements of the 35Cl NQR spin-lattice relaxation time.

Proton NMR Spin-Lattice Relaxation Time Characterization of a-Si(H) Structure

1980 ◽  
Vol 3 ◽  
Author(s):  
M. E. Lowry ◽  
R. G. Barnes ◽  
D. R. Torgeson ◽  
F. R. Jeffrey
Keyword(s):  
Relaxation Time ◽  
Room Temperature ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Mixed Phase ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Nmr Data

ABSTRACTNMR data are presented for reactively sputtered amorphous silicon-hydrogen alloys (a-Si(H)). Measured differences in two of the samples are attributed to two distinct morphologies: a mixed phase (monohydride and dihydride) and a purely monohydride composition. Features of the mixed phase morphology have been modeled. Room temperature, 35 MHz spin-lattice relaxation times are presented for a series of monohydride samples prepared with systematically varied sputtering parameters. A correlation of proton T1 with the density of ESR states tentatively is suggested.

NQR Spin-Lattice Relaxation of Re in Perrhenates

1994 ◽  
Vol 49 (1-2) ◽  
pp. 302-310
Author(s):  
A.J. Szabo ◽  
R. J. C. Brown
Keyword(s):  
Relaxation Time ◽  
Relaxation Process ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Measured Data ◽  
Spin Lattice Relaxation ◽  
Ammonium Ion ◽  
Spin Lattice ◽  
Quadrupolar Relaxation

AbstractThe temperature dependence of the spin-lattice relaxation time T1 for the Re NQR in KReO4 , NH4ReO4 and ND4ReO4 has been measured between 77 K and 323 K. The relaxation is electric quadrupolar in all cases, and because of the large quadrupole moment of Re, T1 is short. In KReO4 T1 follows a T2 dependence. In NH4ReO4 , T1 decreases more rapidly than T-2 above about 100 K; between 170 K and 250 K T1 is smaller than 100 (is and could not be measured, but above 250 K, T1 increases to about 140 μs, and the measured data near room temperature lie close to the T-2 extrapolation from the T1 values below 100 K. These results are interpreted as normal anharmonic Raman quadrupolar relaxation, with a T-2 dependence on temperature, combined with an additional relaxation process due to switching of the ammonium ion between two possible orientations.

scholarly journals Unusual Temperature Dependence of 35Cl NQR Spin-Lattice Relaxation Time in [(CH3)4N]2[MCl6] (M = Pb, Sn, Te)

1991 ◽  
Vol 46 (9) ◽  
pp. 809-814
Author(s):  
Yoshihiro Furukawa ◽  
Yoshihisa Baba ◽  
Shin-ei Gima ◽  
Makoto Kaga ◽  
Tetsuo Asaji ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Unit Cell ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Temperature Dependences

Abstract The temperature dependence of the spin-lattice relaxation time (T1H) of 1H NMR measured in tetramethylammonium hexachloroplumbate(IV), (Me4N)2[PbCl6], showed a deep and a shallow minimum near 190 and 115 K, respectively. Since the presence of two kinds of crystallographically nonequivalent cations in the room-temperature Fd 3c unit cell has been reported, the deep T1H minimum was assigned to the overall reorientation of three quarters of the Me4N+ ions and the shallow minimum to that of the remaining cations. Two different temperature dependences of the chlorine NQR spin-lattice relaxation time (T1Q), attributable to a modulated electric-field-gradient by the protonic motion, were observed in (Me4N)2[MCl6] (M = Pb, Sn, Te). One is found in the Pb complex whose T1Q stems from the cationic motion responsible for the deep T1H minimum, and the other one is determined by the cationic motion giving the shallow T1H minimum. Although all room-temperature phases of these complexes are well described by the Fd 3c unit cell, the presence of different temperature dependences of T1Q suggests that the CH3 groups in the respective complexes take different orientations in the crystals

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