scholarly journals First- and Second-Order Transitions between Quantum and Classical Regimes for the Escape Rate of a Spin System

1997 ◽  
Vol 79 (22) ◽  
pp. 4469-4472 ◽  
Author(s):  
E. M. Chudnovsky ◽  
D. A. Garanin
Keyword(s):  
Spin System ◽  
Second Order ◽  
Escape Rate

scholarly journals Quantum-classical transition of the escape rate of a uniaxial spin system in an arbitrarily directed field

1998 ◽  
Vol 57 (21) ◽  
pp. 13639-13654 ◽  
Author(s):  
D. A. Garanin ◽  
X. Martínez Hidalgo ◽  
E. M. Chudnovsky
Keyword(s):  
Spin System ◽  
Escape Rate ◽  
Classical Transition

Conformational analysis of the products of 1,4 addition of Tri(phenylthio)methyllithium to α,β-unsaturated ketones. The X-ray structuredetermination of 4-Phenyl-5,5,5-tri(phenylthio)pentan-2-one

1981 ◽  
Vol 34 (12) ◽  
pp. 2671
Author(s):  
AB Manas ◽  
RAJ Smith ◽  
J Simpson
Keyword(s):  
Conformational Analysis ◽  
Dihedral Angle ◽  
Spin System ◽  
Title Compound ◽  
Second Order ◽  
Coupling Constants ◽  
X Ray ◽  
Unsaturated Ketones ◽  
Iterative Analysis ◽  
Related Compounds

Iterative analysis of the second-order ABX spin system in the 1H n.m.r. of the title compound gave coupling constants which are consistent with a conformation involving a H-C-C-H dihedral angle of about 90�. The structure was confirmed by X-ray analysis. The 1H n.m.r. of the related compounds 2,2-dimethyl-5-pheny1-6,6,6-tri(phenylthio)hexan-3-one and 1,3-diphenyl-4,4,4-tri(pheny1-thio)butan-1-one were also analysed and found to have similar conformational characteristics.

scholarly journals Quadrupole Excitation in Tunnel Splitting Oscillation in Nanoparticle

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Yousef Yousefi ◽  
Khikmat Kh. Muminov
Keyword(s):  
Magnetic Field ◽  
Spin System ◽  
Easy Axis ◽  
Second Order ◽  
Transverse Anisotropy ◽  
Quadrupole Excitation ◽  
Tunnel Splitting

We analyze the interference between tunneling paths that occur for a spin system with special Hamiltonian both for dipole and quadrupole excitations. Using an instanton approach, we find that as the strength of the second-order transverse anisotropy is increased, the tunnel splitting for both excitations is modulated, with zeros occurring periodically and the number of quenching points for quadrupole excitation decreasing. This effect results from the interference of four tunneling paths connecting easy-axis spin orientations and occurs in the absence of any magnetic field.

scholarly journals Escape rate of a biaxial nanospin system in a magnetic field: First- and second-order transitions between quantum and classical regimes

1999 ◽  
Vol 59 (21) ◽  
pp. 13581-13583 ◽  
Author(s):  
Chang Soo Park ◽  
Sahng-Kyoon Yoo ◽  
D. K. Park ◽  
Dal-Ho Yoon
Keyword(s):  
Magnetic Field ◽  
Second Order ◽  
Escape Rate

scholarly journals Quantum-classical crossover of the escape rate in a biaxial spin system with an arbitrarily directed magnetic field

2000 ◽  
Vol 61 (17) ◽  
pp. 11618-11624 ◽  
Author(s):  
Chang-Soo Park ◽  
Sahng-Kyoon Yoo ◽  
Dal-Ho Yoon
Keyword(s):  
Magnetic Field ◽  
Spin System ◽  
Escape Rate

ESCAPE RATE TRANSITIONS IN THE Fe8 MOLECULAR MAGNET WITH FOURTH-ORDER TRANSVERSE ANISOTROPY

2004 ◽  
Vol 18 (07n08) ◽  
pp. 291-300
Author(s):  
CHANG-SOO PARK
Keyword(s):  
Transition Temperature ◽  
Fourth Order ◽  
Second Order ◽  
Order Transition ◽  
Escape Rate ◽  
Molecular Magnet ◽  
Transverse Anisotropy ◽  
Second Order Transition ◽  
First Order Transition ◽  
Transition Type

We study escape rate transitions in the Fe 8 molecular magnet with fourth-order transverse anisotropy in the presence of an external field perpendicular to the easy axis. Direct numerical diagonalization has been employed to investigate the transition type and the transition temperature T0. We find that the first-order transition as well as the second-order transition can exist when the field is applied along the hard axis, while only the second-order transition appears for the field along the medium axis. It is also observed that the transition temperature is increased due to fourth-order transverse anisotropy.

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