The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Roumen Tsekov - One of the best experts on this subject based on the ideXlab platform.
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temperature dependence of the rate constant for dissociation of absorbed molecules
Chemical Physics Letters, 1992Co-Authors: Georgi N Vayssilov, Roumen TsekovAbstract:Abstract An equation obtained by the Fokker-Planck formalism governing the temperature dependence of the chemical reaction rate constant is discussed. This equation is applied for the reaction of dissociation of a diatomic molecule adsorbed on a solid surface. It is shown that the denominator in the Exponential Term of the rate constant (which is kT in the classical Arrhenius equation) increases for this process as a consequence of the influence of surface phonons.
Boris Mityagin - One of the best experts on this subject based on the ideXlab platform.
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DIVERGENCE OF SPECTRAL DECOMPOSITIONS OF HILL OPERATORS WITH TWO Exponential Term POTENTIALS
Journal of Functional Analysis, 2013Co-Authors: Plamen Djakov, Boris MityaginAbstract:Abstract We consider the Hill operator L y = − y ″ + v ( x ) y , 0 ⩽ x ⩽ π , subject to periodic or antiperiodic boundary conditions (bc) with potentials of the form v ( x ) = a e − 2 i r x + b e 2 i s x , a , b ≠ 0 , r , s ∈ N , r ≠ s . It is shown that the system of root functions does not contain a basis in L 2 ( [ 0 , π ] , C ) if bc are periodic or if bc are antiperiodic and r , s are odd or r = 1 and s ⩾ 3 .
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Divergence of spectral decompositions of Hill operators with two Exponential Term potentials
arXiv: Spectral Theory, 2012Co-Authors: Plamen Djakov, Boris MityaginAbstract:We consider the Hill operator $$ Ly = - y^{\prime \prime} + v(x)y, \quad 0 \leq x \leq \pi, $$ subject to periodic or antiperiodic boundary conditions ($bc$) with potentials of the form $$ v(x) = a e^{-2irx} + b e^{2isx}, \quad a, b \neq 0, r,s \in \mathbb{N}, r\neq s. $$ It is shown that the system of root functions does not contain a basis in $L^2 ([0,\pi], \mathbb{C})$ if $bc$ are periodic or if $bc$ are antiperiodic and $r, s$ are odd or $r=1$ and $s \geq 3. $
Bernard R Brooks - One of the best experts on this subject based on the ideXlab platform.
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a double Exponential potential for van der waals interaction
AIP Advances, 2019Co-Authors: Bernard R BrooksAbstract:Van der Waals (vdw) interaction is an important force between atoms and molecules. Many potential functions have been proposed to model vdw interaction such as the Lennard-Jones (L-J) potential. To overcome certain drawbacks of existing function forms, this work proposes a double Exponential (DE) potential that contains a repulsive Exponential Term and an attractive Exponential Term. This potential decays faster than the L-J potential and has a soft core. The DE potential is very flexible and its two Exponential parameters can be adjusted continuously to mimic many potential functions. Combined with the isotropic periodic sum (IPS) method, the DE potential can efficiently and accurately describe non-bonded interactions and is convenient for alchemical free energy calculation.Van der Waals (vdw) interaction is an important force between atoms and molecules. Many potential functions have been proposed to model vdw interaction such as the Lennard-Jones (L-J) potential. To overcome certain drawbacks of existing function forms, this work proposes a double Exponential (DE) potential that contains a repulsive Exponential Term and an attractive Exponential Term. This potential decays faster than the L-J potential and has a soft core. The DE potential is very flexible and its two Exponential parameters can be adjusted continuously to mimic many potential functions. Combined with the isotropic periodic sum (IPS) method, the DE potential can efficiently and accurately describe non-bonded interactions and is convenient for alchemical free energy calculation.
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A double Exponential potential for van der Waals interaction.
AIP advances, 2019Co-Authors: Bernard R BrooksAbstract:Van der Waals (vdw) interaction is an important force between atoms and molecules. Many potential functions have been proposed to model vdw interaction such as the Lennard-Jones (L-J) potential. To overcome certain drawbacks of existing function forms, this work proposes a double Exponential (DE) potential that contains a repulsive Exponential Term and an attractive Exponential Term. This potential decays faster than the L-J potential and has a soft core. The DE potential is very flexible and its two Exponential parameters can be adjusted continuously to mimic many potential functions. Combined with the isotropic periodic sum (IPS) method, the DE potential can efficiently and accurately describe non-bonded interactions and is convenient for alchemical free energy calculation.
A G Bratsos - One of the best experts on this subject based on the ideXlab platform.
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An explicit numerical scheme for the modified Burgers' equation
International Journal for Numerical Methods in Biomedical Engineering, 2011Co-Authors: A G Bratsos, L. A. PetrakisAbstract:An explicit finite difference scheme based on second-order rational approximants to the matrix-Exponential Term is proposed for the numerical solution of the modified Burgers' equation already known in the bibliography. The method, which is analyzed for local truncation error and stability, is tested to various wave packets and the results arising from the experiments are compared with the relevant known ones. Copyright © 2009 John Wiley & Sons, Ltd.
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A fourth-order numerical scheme for solving the modified Burgers equation
Computers & Mathematics with Applications, 2010Co-Authors: A G BratsosAbstract:A finite-difference scheme based on fourth-order rational approximants to the matrix-Exponential Term in a two-time level recurrence relation is proposed for the numerical solution of the modified Burgers equation. The resulting nonlinear system, which is analyzed for stability, is solved using an already known modified predictor-corrector scheme. The results arising from the experiments are compared with the corresponding ones known from the available literature.
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a second order numerical scheme for the improved boussinesq equation
Physics Letters A, 2007Co-Authors: A G BratsosAbstract:A finite-difference scheme arising from the use of rational approximants to the matrix-Exponential Term in a three-time level recurrence relation is used for the numerical solution of the improved Boussinesq equation (IBq). The resulting linear scheme, which is analyzed for local truncation error and stability, is tested numerically and conclusions with corresponding results known in the bibliography are derived.
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The solution of the Boussinesq equation using the method of lines
Computer Methods in Applied Mechanics and Engineering, 1998Co-Authors: A G BratsosAbstract:Abstract The method of lines is used to transform the initial/boundary-value problem associated with the nonlinear hyperbolic Boussinesq equation, into a first-order, nonlinear, initial-value problem. Numerical methods are developed by replacing the matrix-Exponential Term in a recurrence relation by rational approximants. The resulting finite-difference methods are analysed for local truncation errors, stability and convergence. The results of a number of numerical experiments are given.
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The solution of the sine-gordon equation using the method of lines
International Journal of Computer Mathematics, 1996Co-Authors: A G Bratsos, Edward H. TwizellAbstract:The method of lines is used to transform the initial/boundary-value problem assckiated with the nonlinear hyperbolic sine-Gordon equation, into a first-order, nonlinear, initial-vjalue problem. Numerical methods are developed by replacing the matrix-Exponential Term \n a recurrence relation by rational approximants. The resulting finite-difference methods ar|e analysed for local truncation errors, stability and convergence. The results of a number of numerical experiments are given.
Denis Michel - One of the best experts on this subject based on the ideXlab platform.
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A probabilistic rate theory connecting kinetics to thermodynamics
Physica A: Statistical Mechanics and its Applications, 2018Co-Authors: Denis MichelAbstract:Kinetics and thermodynamics are largely disconnected in current theories because Arrhenius activation energies (Ea) have strictly no influence on equilibrium distributions. A first step towards the incorporation of rate theories in thermodynamics was the identification of the pre-Exponential Term of the Arrhenius equation as an entropic quantity. The second step examined here is the possible contribution of Ea in equilibrium landscapes. Interestingly, this possibility exists if envisioning the energetic Exponential Term of rates constants as the probability that the energy of the reactant is sufficient for the transition. This radically new approach, which encompasses Maxwell-Boltzmann distributions as particular cases, solves inconsistencies in previous theories, for instance on the role of temperature in kinetics and thermodynamics. These probabilistic rate constants are then reintroduced in dynamic systems to provide them with the two distinct facets of time: the time step and the time arrow.
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A probabilistic rate theory connecting kinetics to thermodynamics
Physica A: Statistical Mechanics and its Applications, 2018Co-Authors: Denis MichelAbstract:Kinetics and thermodynamics are largely disconnected in current theories because Arrhenius activation energies (Ea) have strictly no influence on equilibrium distributions. A first step towards the incorporation of rate theories in thermodynamics is the identification of the pre-Exponential Term of the Arrhenius equation as an entropic quantity. A second step examined here is the possible contribution of Ea in equilibrium landscapes. Interestingly, this possibility exists if envisioning the energetic Exponential Term of Arrhenius rate constants as the probability that the energy of the reactant is sufficient for the transition. This radically new approach encompasses Maxwell–Boltzmann distributions and solves inconsistencies in previous theories, in particular on the role of temperature in kinetics and thermodynamics. These probabilistic rate constants are then reintroduced in dynamic systems to provide them with the two distinct facets of time the time step and the time arrow. © 2018 Elsevier B.V.
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A probabilistic rate theory connecting kinetics to thermodynamics
2017Co-Authors: Denis MichelAbstract:Kinetics and thermodynamics are largely disconnected in current theories because Arrhenius activation energies (Ea) have strictly no influence on equilibrium distributions. A first step towards the incorporation of rate theories in thermodynamics is the identification of the pre-Exponential Term of the Arrhenius equation as an entropic quantity. A second step examined here is the possible contribution of Ea in equilibrium landscapes. Interestingly, this possibility exists if envisioning the energetic Exponential Term of Arrhenius rate constants as the probability that the energy of the reactant is sufficient for the transition. This radically new approach encompasses Maxwell-Boltzmann distributions and solves inconsistencies in previous theories, in particular on the role of temperature in kinetics and thermodynamics. These probabilistic rate constants are then reintroduced in dynamic systems to provide them with the two distinct facets of time: the time step and the time arrow.
