scholarly journals Nanoscale rotational dynamics of four independent rotators confined in crowded crystalline layers

Nanoscale ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 8294-8302 ◽  
Author(s):  
Antonio Rodríguez-Fortea ◽  
Enric Canadell ◽  
Pawel Wzietek ◽  
Cyprien Lemouchi ◽  
Magali Allain ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Lattice Relaxation ◽  
Rotational Dynamics ◽  
Microscopic Model ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Rotational Barriers ◽  
Correlated Motion ◽  
Relaxation Maximum

Car–Parrinello molecular dynamics unravels a microscopic model of correlated motion within a set of four rotors whose similar rotational barriers (at 6 kcal mol−1) are encapsulated within a broad 1H spin–lattice relaxation maximum.

Molecular Motion in Tetraphenyltin Studied by NMR

1999 ◽  
Vol 54 (8-9) ◽  
pp. 488-494
Author(s):  
A. Pajzderska ◽  
J. Wąsicki ◽  
S. Lewicki
Keyword(s):  
Phenyl Ring ◽  
Room Temperature ◽  
Molecular Motion ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Ring Rotation ◽  
Phenyl Rings ◽  
Correlated Motion

NMR second moment and spin-lattice relaxation times in the laboratory (60 and 25 MHz) and in therotating frame (B1 = 2.1 mT) were studied for polycrystalline tetraphenyltin Sn(C6H5)4 in a wide temperaturerange. Two kinds of motions were detected: isotropic rotation of whole molecules and reorientations/oscillations of phenyl rings. A dependence of the potential energy of the molecule in the crystalon the angle of the phenyl ring rotation about the Sn-C bond was obtained on the basis of atom-atomcalculations. The amplitude of the ring-oscillations at 133 K was estimated as ± 7°. Below room temperaturethe magnetisation recovery is significantly non-exponential, which may be interpreted as dueto the correlated motion of phenyl rings.

Proton NMR Study of Molecular Dynamics in Hydrazinium Perchlorate

1990 ◽  
Vol 45 (2) ◽  
pp. 102-106
Author(s):  
K. Ganesan ◽  
R. Damle ◽  
J. Ramakrishna
Keyword(s):  
Molecular Dynamics ◽  
Relaxation Time ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Temperature Minimum ◽  
Second Moment ◽  
Spin Lattice ◽  
Nmr Study

AbstractThe proton spin-lattice relaxation time T1 (at 5.4, 10 and 15 MHz) and second moment M2 (at 9.8 MHz) have been measured in hydrazinium Perchlorate (N2H5ClO4). The temperature dependence of T, shows two minima. The low temperature T, minimum has been explained in terms of NH3 reorientation about the N-N axis while the high temperature minimum is attributed to the exchange of protons within the NH2 group (180° flip about the H - N - H bisectrix). The activation energies for NH3 and NH: motions are found to be 20.5 kJ mol-1 and 39.8 kJ mol-1 , respectively. The second moment variation with temperature shows two transitions around 120 K and 210 K and has been discussed in terms of NH3/NH2 motions.

Spin-lattice relaxation in ammonium compounds with a complex molecular dynamics

1997 ◽  
Vol 8 (2) ◽  
pp. 89-107 ◽  
Author(s):  
Z.T. Lalowicz ◽  
M. Punkkinen ◽  
A.H. Vuorimäki ◽  
E.E. Ylinen ◽  
A. Detken ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Ammonium Compounds
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