Kinetics of the oxidation of [N-(2-hydroxyethyl)-ethylene-diamine-N,N′,N′-triacetato]cobalt(II) by N-bromosuccinimide

The kinetics of the oxidation of [N-(2-hydroxyethyl)-ethylene-diamine-N,N,N-triacetato] cobalt(II), [Co^II-(HEDTA)]^–, by N-bromosuccinimide, NBS, have been studied in aqueous solutions and water-methanol solvent mixtures under various conditions. The reaction stoichiometry indicates that one mole of NBS reacts with one mole of [Co^II(HEDTA)]^–. In aqueous solutions the reaction obeys the following rate law:

Kinetics and mechanism of oxidation oftrans-1,2-diaminocyclohexanetetraacetatocobaltate(II) by periodate

Summary The kinetics of oxidation oftrans-1,2-diaminocyclohexanetetraacetatocobaltate(II), Co^IICDTA^2–, by periodate were studied using either excess periodate or excess complex concentrations. When periodate was in excess the reaction showed first-order dependence on [IO ₄ ^– ] and first-order and second-order dependences on [Co^IICDTA^2–]. First-order dependence in each reactant was obtained when the complex was in excess. The reaction rate was found to be independent of pH over the range 4–5, but increasing with increasing ionic strength. The enthalpy and the entropy of activation were calculated using the transition state theory equation.     

Kinetics and mechanism of the oxidation of a ternary complex involving nitrilotriacetatocobaltate(II) and malonic acid by N-bromosuccinimide

The kinetics of oxidation of [Co^IINM(H₂O)]^3– (N = nitrilotriacetate, M = malonate) by N-bromosuccinimide (NBS) in aqueous solution have been found to obey the equation: d[Co^III]/dt = k ₁ K ₂[NBS][Co^II]_T/{1 + K₂[NBS] + (H⁺/K₁)} where k ₁ is the rate constant for the electron transfer process, K ₁ the equilibrium constant for dissociation of [Co^IINM(H₂O)]^3– to [Co^IINM(OH)]^4– + H⁺, and K ₂ the pre-equilibrium formation constant. Values of k ₁ = 1.07 × 10^–3 s^–1, K ₁ = 4.74 × 10^–8 mol dm^–3 and K ₂ = 472 dm³ mol^–1 have been obtained at 30 °C and I = 0.2 mol dm^–3. The thermodynamic activation parameters have been calculated. The experimental rate law is consistent with a mechanism in which the deprotonated [Co^IINM(OH)]^4– is considered to be the most reactive species compared to its conjugate acid. It is assumed that electron transfer takes place via an inner-sphere mechanism.     

Kinetics and mechanism of oxidation of the chromium(III)-DL-aspartic acid complex/periodate reaction. Evidence for iron(II) catalysis

The kinetics of oxidation of the chromium(III)-DL- aspartic acid complex, [CrIIIHL]+ by periodate have been investigated in aqueous medium. In the presence of Fe^II as a catalyst, the following rate law is obeyed:

Quantum Phase and Field Purification for Quantum System in Coherent States Based on Generalized Heisenberg Algebra

In this paper, we consider the interaction between the two-level atom and the electromagnetic field modes initially prepared in coherent states associated with the generalized Heisenberg algebra (GHA). We investigate the dynamical behavior of the field purity, Pancharatnam phase, and atomic-population inversion. Based on the GHA, we study the statistical properties of the field state through the evolution of the Mandel parameter and examine the effects of the initial atomic state setting and the number of transiting photons. The results show that the GHA-coherent-state strength has the potential to affect the time evolution of the field purification, the Pancharatnam phase, and the Mandel parameter.     

Erratum to “Effect of the time-dependent coupling on a superconducting qubit-field system under decoherence: Entanglement and Wehrl entropy” [Ann. Physics 361 (2015) 247–258]

The dynamics of a superconducting (SC) qubit interacting with a field under decoherence with and without time-dependent coupling effect is analyzed. Quantum features like the collapse–revivals for the dynamics of population inversion, sudden birth and sudden death of entanglement, and statistical properties are investigated under the phase damping effect. Analytic results for certain parametric conditions are obtained. We analyze the influence of decoherence on the negativity and Wehrl entropy for different values of the physical parameters. We also explore an interesting relation between the SC-field entanglement and Wehrl entropy behavior during the time evolution. We show that the amount of SC-field entanglement can be enhanced as the field tends to be more classical. The studied model of SC-field system with the time-dependent coupling has high practical importance due to their experimental accessibility which may open new perspectives in different tasks of quantum formation processing.     

Sudden Death,Sudden Birth,and Nonclassical Effects of Photon-Added Power-Law Potential Within the Framework of Subsystem-Environment Correlations

Recently photon-added states that could be detected through the emission rather than the absorption of electromagnetic radiation have been actively explored and investigated. In this paper, we construct the photon-added power-law-potential coherent states (PA-PLPCSs) using generalized Heisenberg algebra. The Klauder minimal set of conditions required to obtain coherent states are satisfied. We study nonclassical effects associated with PA-PLCSs using the Mandel parameter and discuss some of their intriguing nonclassical behavior. These states have interesting significance and can be realized experimentally, exhibiting highly nonclassical behavior that depends on the degree of excitation and other parameters. Finally, we study the dynamics of entanglement and quantum discord for two-mode state within the framework of PLPCSs and show that the sudden death and sudden birth of correlations are due to the change and transfer of the correlation between one mode and its environment, using the monogamic relation between the entanglement and quantum discord.     

Tavis–Cummings Model with Moving Atoms

In this work, we examine a nonlinear version of the Tavis–Cummings model for two two-level atoms interacting with a single-mode field within a cavity in the context of power-law potentials. We consider the effect of the particle position that depends on the velocity and acceleration, and the coupling parameter is supposed to be time-dependent. We examine the effect of velocity and acceleration on the dynamical behavior of some quantumness measures, namely as von Neumann entropy, concurrence and Mandel parameter. We have found that the entanglement of subsystem states and the photon statistics are largely dependent on the choice of the qubit motion and power-law exponent. The obtained results present potential applications for quantum information and optics with optimal conditions.     

The effect of atomic motion and two-quanta JCM on the information entropy

We study the interaction between a moving two-level atom and a single-mode field. The coupled atom-cavity system with atomic center-of-mass motion included is modeled by considering the dependence of the atomic motion along z-axis. At exact resonance between the internal atomic transition and the cavity eigenfrequency, an exact solution of the system is obtained and periodically modulated Rabi oscillations and regular translational motion are observed. We focused on the dynamics of both field Wehrl entropy and Wehrl phase distribution. The influence of the atomic motion on the evolution of von Neumann entropy and Wehrl entropy is examined. The results show that the atomic motion and the field-mode structure play important roles in the evolution of the von Neumann entropy, Wehrl entropy and Wehrl PD.     

Pancharatnam and total phases for one-dimensional photonic band gaps

We study the time evolution of the total and Pancharatnam phase of four-level atoms in the presence of a one-dimensional photonic-band-gap material. We obtain analytical and numerical results under certain parametric conditions and analyze the effect of a Kerr-like medium and the detuning parameter on the dynamics of the Pancharatnam phase for the initial atomic position. We observe an interesting feature of the Pancharatnam phase for the one-dimensional photonic-band-gap material.