Search results for "Rate equation"

Rate Equation Network for Baryon Production in High Energy Nuclear Collisions

2003

We develop and solve a network of rate equations for the production of baryons and anti-baryons in high energy nuclear collisions. We include all members of the baryon octet and decuplet and allow for transformations among them. This network is solved during a relativistic 2+1 hydrodynamical expansion of the of the hot matter created in the collision. As an application we compare to the number of protons, lambdas, negative cascades, and omega baryons measured at mid-rapidity in central collisions of gold nuclei at 65 GeV per nucleon at the Relativistic Heavy Ion Collider (RHIC).

Design of Er3+-doped chalcogenide glass laser for MID-IR application

2009

Abstract The feasibility of a photonic crystal fiber laser (PCF laser), made of a novel Er 3+ -doped chalcogenide glass and operating at the wavelength λ s  = 4.5 μm is investigated. The design is performed on the basis of spectroscopic and optical parameters measured on a fabricated Er 3+ -doped Ga 5 Ge 20 Sb 10 S 65 chalcogenide bulk sample. The simulations have been performed by employing a home made numerical code that solves the multilevel rate equations and the power propagation equations via a Runge-Kutta iterative method. The numerical results indicate that a laser exhibiting slope efficiency close to the maximum theoretical one and a wide tunability in the wavelengths range where t…

Phonon Bandwidth and Rate Equations in Avalanche Relaxation

1973

Coherent effects in the multimode dynamics of inhomogeneously broadened ring lasers

2004

We investigate under which conditions coherent effects manifest in the multimode dynamics of inhomogeneously broadened ring lasers. In particular, we demonstrate that for long enough cavities standard rate equations for class-B lasers fail in describing the multimode dynamics.

Generalized rate equations for multimode lasers

2003

Abstract A generalized rate equations model for class B lasers outside the uniform field limit is presented. This model allows to correctly describe the Risken–Nummedal–Graham–Haken instability and its associated multimode dynamics. When parameters suitable for fiber lasers – where the instability has been observed – are adopted, the computation time is shown to be greatly reduced with respect to the complete model based on the full set of Maxwell–Bloch (MB) equations.

Modeling of a tunable-barrier non-adiabatic electron pump beyond the decay cascade model

2014

We generalize the decay cascade model of charge capture statistics for a tunable-barrier non-adiabatic electron pump dominated by the backtunneling error at the quantum dot decoupling stage. The energy scales controlling the competition between the thermal and the dynamical mechanisms for accurate trapped charge quantization are discussed. Empirical fitting formula incorporating quantum dot re-population errors due to particle-hole fluctuations in the source lead is suggested and tested against an exactly solvable rate equation model.

Time-dependent density-functional theory of strong-field ionization of atoms by soft x rays

2014

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).-- et al.

Validity of rate equations for Zeeman coherences for analysis of nonlinear interaction of atoms with broadband laser radiation

2004

In this paper we, to our knowledge, for the first time obtain the rate equations for Zeeman coherences in the broad line approximation and steady-state balance equations directly from optical Bloch equations without the use of the perturbation theory. The broad line approximation allows us to use the adiabatic elimination procedure in order to eliminate the optical coherences from the optical Bloch equations, but the steady-state condition allows us to derive the balance equations straightforward. We compare our approach with the perturbation theory approach as given previously and show that our approach is more flexible in analyzing various experiments. Meanwhile we also show the validity …

Dynamic Characterization of Upconversion in Highly Er-Doped Silica Photonic Crystal Fibers

2012

Measurements of time evolution of amplified spontaneous emission for square-wave modulated pump were made on a highly erbium-doped silica photonic crystal fiber and fitted to theoretical results calculated using different formalisms to describe the ${\rm Er}^{3+}$ -ion migration-assisted co-operative upconversion mechanism in the population densities rate equations. The determined characterization parameters are the constant homogeneous upconversion coefficient, 3.0 $\times 10^{-24}~{\rm m}^{3}/{\rm s}$ , the critical radii for upconversion and migration, 10.5 and 14A, respectively, and the rate of clustered ions, 14%. These parameters are analysed and compared to those obtained with contin…

A combined experimental and theoretical study of the unimolecular elimination kinetics of 2-alkoxypropionic acids in the gas phase

1999

Abstract The reaction mechanism associated with the decomposition of three 2-alkoxypropionic acids (2-methoxy-, 2-ethoxy- and 2-isopropoxypropionic acid) in gas phase to form acetaldehyde, carbon monoxide, and the corresponding alcohol has been analyzed by a combination of experimental and theoretical studies. The kinetics of these systems were determined in a static system over the temperature and pressure range of 301.2–370.7°C and 61–190 Torr, respectively, in seasoned vessel, with the free-radical inhibitor cyclohexene. The experimental data show that these decompositions are homogeneous, unimolecular and follow a first-order rate law. A detailed characterization, at MP2/6-31G** computa…