Spin locking of I=3/2 nuclei in static and spinning samples: A description by abstract spins and Floquet formalism

1998 ◽  
Vol 108 (3) ◽  
pp. 907-917 ◽  
Author(s):  
Gunnar Jeschke
Keyword(s):  
2014 ◽  
Vol 7 (8) ◽  
pp. 2739-2752 ◽  
Author(s):  
A. Dunst ◽  
V. Epp ◽  
I. Hanzu ◽  
S. A. Freunberger ◽  
M. Wilkening

Conductivity spectroscopy and 7Li spin-locking NMR relaxometry reveal enhanced ion dynamics in nanocrystalline Li2O2 prepared by high-energy ball milling.


1978 ◽  
Vol 11 (6) ◽  
pp. L223-L226 ◽  
Author(s):  
R A Wind ◽  
J H N Creyghton ◽  
D J Ligthelm ◽  
J Smidt

2018 ◽  
Vol 17 (4) ◽  
Author(s):  
S. A. Gerasev ◽  
A. V. Fedorova ◽  
E. B. Fel’dman ◽  
E. I. Kuznetsova

Author(s):  
Ana Jonas ◽  
Xiangdong Peng

We have used 2H NMR methods to examine the order and dynamics of dipalmitoylphosphatidylcholine (DPPC) in multilamellar and small unilamellar vesicles in water as a function of pressure. Multipulse 2H NMR techniques were used with selectively deuterated DPPC on both chains at positions C-2, C-9, or C-13, to obtain lineshapes, spin-lattice relaxation times (T1), and spin-spin relaxation times (T2) at 50 °C from 1 bar to 5.2 kbar pressure. This pressure range allowed us to explore the phase behavior of DPPC from the liquid crystalline (LC) phase through various gel phases (Gl, Gll, Glll, GX), including the interdigited Gi phase. Pressure has an ordering effect: on all chain segments in all the phases. In the LC phase, the order parameter (SCD) decreases from C-2 > C-9 > C-13, while in the gel phases SCD decreases from C-9 > C-13 > C-2, indicating that in the gel phases the middle segments of the chains are more restricted in their motions than the ends. In the LC phase, T1 and T2 values for all segments decrease with pressure and have an order from C-13 > C-9 > C-2. These results suggest that similar conformational motions and molecular rotational motions occur in the LC state in all segments, but have increased amplitudes and frequencies toward the methyl ends. At the phase transitions, discontinuities and abrupt reversal of the slopes for the T1 or T2 dependences on pressure indicate major changes in motional modes and rates for DPPC molecules in the different structures. In the second part of this study, we have measured the lateral diffusion of DPPC in sonicated vesicles in D2O as a function of pressure. The spin-lattice relaxation rate in the rotating frame T−11p was plotted as a function of the square root of the spin-locking field angular frequency (ω1)1/2, and the lateral diffusion coefficient (D) was calculated from the slope. Pressure effects are observed on lateral diffusion in the LC phase (D = 5.4 − 2 × 10−9 cm2 seconds, from 1 to 300 bar) but are negligible in the GI phase (D ≈ 1.0 × 10−9 cm2 seconds, from 400 to 800 bar).


2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Leonid V. Abdurakhimov ◽  
Imran Mahboob ◽  
Hiraku Toida ◽  
Kosuke Kakuyanagi ◽  
Yuichiro Matsuzaki ◽  
...  
Keyword(s):  

2003 ◽  
Vol 162 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Sridhar R. Charagundla ◽  
Arijitt Borthakur ◽  
John S. Leigh ◽  
Ravinder Reddy
Keyword(s):  

2013 ◽  
Vol 15 (34) ◽  
pp. 14248 ◽  
Author(s):  
Alexey S. Kiryutin ◽  
Konstantin L. Ivanov ◽  
Alexandra V. Yurkovskaya ◽  
Hans-Martin Vieth ◽  
Nikita N. Lukzen

1996 ◽  
Vol 51 (5-6) ◽  
pp. 357-362 ◽  
Author(s):  
B. Bandyopadhyay ◽  
G. B. Furman ◽  
S. D. Goren ◽  
C. Korn ◽  
A. L Shames

Abstract The response of a quadrupolar spin system in zero applied magnetic field to a long rf pulse, for both single crystal and polycrystalline samples possessing broad Lorentzian-shaped resonance lines has been studied. The dependencies of magnetization on frequency offset, linewidth and power are investigated both theoretically and experimentally. The problem of the effective field direction in both single crystal and polycrystalline samples is also discussed. For a polycrystalline cuprous oxide (Cu2O) sample it is observed that the magnetization after a long pulse in on-resonance condition does not become zero for time t ≫ T2 , in agreement with theoretical results. It has also been shown that the magnetization increases with increase in the width of the resonance line as well as with the decrease in the excitation power.


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