scholarly journals Substrate Ground State Binding Energy Concentration Is Realized as Transition State Stabilization in Physiological Enzyme Catalysis

BMB Reports ◽  
2004 ◽  
Vol 37 (5) ◽  
pp. 533-537 ◽  
Author(s):  
Billy Mark Britt
2008 ◽  
Vol 22 (12) ◽  
pp. 1923-1932
Author(s):  
JIA LIU ◽  
ZI-YU CHEN

The influence of a perpendicular magnetic field on a bound polaron near the interface of a polar–polar semiconductor with Rashba effect has been investigated. The material is based on a GaAs / Al x Ga 1-x As heterojunction and the Al concentration varying from 0.2 ≤ x ≤ 0.4 is the critical value below which the Al x Ga 1-x As is a direct band gap semiconductor.The external magnetic field strongly altered the ground state binding energy of the polaron and the Rashba spin–orbit (SO) interaction originating from the inversion asymmetry in the heterostructure splitting of the ground state binding energy of the bound polaron. How the ground state binding energy will be with the change of the external magnetic field, the location of a single impurity and the electron area density have been shown in this paper, taking into account the SO coupling. The contribution of the phonons are also considered. It is found that the spin-splitting states of the bound polaron are more stable, and, in the condition of weak magnetic field, the Zeeman effect can be neglected.


1989 ◽  
Vol 67 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Magne Haugen ◽  
Erlend Østgaard

The ground-state energy of spin-polarized hydrogen, deuterium, and tritium is calculated by means of a modified variational lowest order constrained-variation method, and the calculations are done for five different two-body potentials. Spin-polarized H↓ is not self-bound according to our theoretical results for the ground-state binding energy. For spin-polarized D↓, however, we obtain theoretical results for the ground-state binding energy per particle from −0.42 K at an equilibrium particle density of 0.25 σ−3 or a molar volume of 121 cm3/mol to + 0.32 K at an equilibrium particle density of 0.21 σ−3 or a molar volume of 142 cm3/mol, where σ = 3.69 Å (1 Å = 10−10 m). It is, therefore, not clear whether spin-polarized deuterium should be self-bound or not. For spin-polarized T↓, we obtain theoretical results for the ground-state binding energy per particle from −4.73 K at an equilibrium particle density of 0.41 σ−3 or a molar volume of 74 cm3/mol to −1.21 K at an equilibrium particle density of 0.28 σ−3 or a molar volume of 109 cm3/mol.


2003 ◽  
Vol 101 (17) ◽  
pp. 2695-2714 ◽  
Author(s):  
KARA E. RANAGHAN ◽  
LARS RIDDER ◽  
BORYS SZEFCZYK ◽  
W. ANDRZEJ SOKALSKI ◽  
JOHANNES C. HERMANN ◽  
...  

2016 ◽  
Vol 954 ◽  
pp. 149-160 ◽  
Author(s):  
F. Schulz ◽  
P. Achenbach ◽  
S. Aulenbacher ◽  
J. Beričič ◽  
S. Bleser ◽  
...  

1989 ◽  
Vol 67 (9) ◽  
pp. 1440-1448 ◽  
Author(s):  
Edward J. Dunn ◽  
Erwin Buncel

The effect of macrocyclic crown ether and cryptand complexing agents on the rate of the nucleophilic displacement reaction of p-nitrophenyl diphenylphosphinate by alkali metal ethoxides in ethanol at 25 °C has been studied by spectrophotometric techniques. For the reactions of potassium ethoxide, sodium ethoxide, and lithium ethoxide, the observed rate constant increased in the order KOEt < NaOEt < LiOEt. Crown ether and cryptand cation-complexing agents have a retarding effect on the rate. Increasing the ratio of complexing agent to base results in a decrease in kobs to a minimum value corresponding to the rate of reaction of free ethoxide ion. In complementary experiments, alkali metal ions were added to these reaction systems in the form of unreactive salts, causing an increase in reaction rate. The kinetic data were analysed in terms of ion-pairing treatments, which allowed evaluation of rate coefficients due to free ethoxide ions and metal ion – ethoxide ion pairs. Possible roles of the metal cations are discussed in terms of ground state and transition state stabilization. Evaluation of the equilibrium constants for association of the metal ion with ground state (Ka) and the transition state (K′a) shows that catalysis occurs as a result of enhanced association between the metal ion and the transition state, with (K′a) values increasing in the order K+ < Na+ < Li+. A model is proposed in which transition state stabilization arises largely from chelation of the solvated metal ion to two charged oxygen centers. This appears to be the first reported instance of catalysis by alkali metal cations in nucleophilic displacement at phosphoryl centers. Keywords: nucleophilic displacement at phosphorus, alkali-metal-ion catalysis.


2016 ◽  
Vol 31 (14) ◽  
pp. 1650084 ◽  
Author(s):  
A. Armat ◽  
H. Hassanabadi

In this work, the ground state binding energy of [Formula: see text]-particle in hypernuclei is investigated by using analytical solution of non-relativistic Schrödinger equation in the presence of a generalized Woods–Saxon-type interaction. The comparison with the experimental data is motivating.


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