Energy surface model of single particle reversal in sub-Stoner–Wohlfarth switching fields

2003 ◽  
Vol 93 (10) ◽  
pp. 6549-6551 ◽  
Author(s):  
Kai-Zhong Gao ◽  
Eric D. Boerner ◽  
H. Neal Bertram
Keyword(s):  
Single Particle ◽  
Energy Surface ◽  
Surface Model

Two 0+ excited states in 40Ca with diabatic and adiabatic constrained approaches

2014 ◽  
Vol 23 (01) ◽  
pp. 1450003
Author(s):  
H. Y. Sang ◽  
X. S. Wang ◽  
J. H. Wang ◽  
Y. Y. Liu ◽  
H. F. Lü
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Excited States ◽  
Single Particle ◽  
Energy Surface ◽  
Center Of Mass ◽  
Mean Field ◽  
Mass Motion ◽  
Relativistic Mean Field

Two 0+ excited states of 40 Ca have been investigated by the potential energy surface (PES) obtained from both adiabatic and diabatic constrained approaches, combined with the relativistic mean field (RMF) theory. A well-defined second minimum appears on the diabatic PES that does not exists on the adiabatic PES. The configurations of these two 0+ excited states are determined as 4p–4h and 8p–8h excitation from their counterparts at the spherical configuration. The excited energies were reduced by microscopic correction for the center-of-mass motion, and a gap at 18 appears in their single particle diagrams.

scholarly journals Pathways for nicotinic receptor desensitization

2020 ◽  
Vol 152 (10) ◽  
Author(s):  
Anthony Auerbach
Keyword(s):  
Transition State ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Open Channel ◽  
Energy Surface ◽  
Surface Model ◽  
Closed Channel ◽  
Discrete State ◽  
State Region ◽  
Selection Of

Nicotinic acetylcholine receptors (AChRs) are ligand-gated ion channels that generate transient currents by binding agonists and switching rapidly between closed- and open-channel conformations. Upon sustained exposure to ACh, the cell response diminishes slowly because of desensitization, a process that shuts the channel even with agonists still bound. In liganded receptors, the main desensitization pathway is from the open-channel conformation, but after agonists dissociate the main recovery pathway is to the closed-channel conformation. In this Viewpoint, I discuss two mechanisms that can explain the selection of different pathways, a question that has puzzled the community for 60 yr. The first is based on a discrete-state model (the “prism”), in which closed, open, and desensitized conformational states interconnect directly. This model predicts that 5% of unliganded AChRs are desensitized. Different pathways are taken with versus without agonists because ligands have different energy properties (φ values) at the transition states of the desensitization and recovery reactions. The second is a potential energy surface model (the “monkey saddle”), in which the states connect indirectly at a shared transition state region. Different pathways are taken because agonists shift the position of the gating transition state relative to the point where gating and desensitization conformational trajectories intersect. Understanding desensitization pathways appears to be a problem of kinetics rather than of thermodynamics. Other aspects of the two mechanisms are considered, as are experiments that may someday distinguish them.

Phase transition at N = 92 in 158Dy

2016 ◽  
Vol 25 (10) ◽  
pp. 1650076 ◽  
Author(s):  
J. B. Gupta
Keyword(s):  
Phase Transition ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Single Particle ◽  
Degrees Of Freedom ◽  
Energy Surface ◽  
Transition Rates ◽  
Microscopic Approach ◽  
Shape Phase Transition

Beyond the shape phase transition from the spherical vibrator to the deformed rotor regime at [Formula: see text], the interplay of [Formula: see text]- and [Formula: see text]-degrees of freedom becomes important, which affects the relative positions of the [Formula: see text]- and [Formula: see text]-bands. In the microscopic approach of the dynamic pairing plus quadrupole model, a correlation of the strength of the quadrupole force and the formation of the [Formula: see text]- and [Formula: see text]-bands in [Formula: see text]Dy is described. The role of the potential energy surface is illustrated. The [Formula: see text] transition rates in the lower three [Formula: see text]-bands and the multi-phonon bands with [Formula: see text] and [Formula: see text] are well reproduced. The absolute [Formula: see text] [Formula: see text] serves as a good measure of the quadrupole strength. The role of the single particle Nilsson orbits is also described.

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