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81.
Kreidi K Akoury D Jahnke T Weber T Staudte A Schöffler M Neumann N Titze J Schmidt LP Czasch A Jagutzki O Costa Fraga RA Grisenti RE Smolarski M Ranitovic P Cocke CL Osipov T Adaniya H Thompson JC Prior MH Belkacem A Landers AL Schmidt-Böcking H Dörner R 《Physical review letters》2008,100(13):133005
We investigate single-photon double ionization of H(2) by 130 to 240 eV circularly polarized photons. We find a double slitlike interference pattern in the sum momentum of both electrons in the molecular frame which survives integration over all other degrees of freedom. The difference momentum and the individual electron momentum distributions do not show such a robust interference pattern. We show that this interference results from a non-Heitler-London fraction of the H(2) ground state where both electrons are at the same atomic center. 相似文献
82.
Dauvergne D Belkacem A Barrué F Bocquet JP Chevallier M Feinberg B Kirsch R Poizat JC Ray C Rebreyend D 《Physical review letters》2003,90(15):153002
We report a measurement of photon impact ionization of K and L shell of Au and K shell of Ag targets in the 1-GeV energy range. We show that the cross section is dominated by a contribution from a new channel called vacuum-assisted photoionization. In this process the energy-momentum balance associated with the removal of the innershell electron is obtained by conversion of a high-energy photon into an electron-positron pair. This measurement is consistent with the theoretical prediction that vacuum-assisted photoionization is the most probable ionization mechanism at very high energies. 相似文献
83.
Belkacem Said-Houari 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2011,110(1):115-133
This work is concerned with a system of nonlinear viscoelastic wave equations with nonlinear damping and source terms acting
in both equations. We will prove that the energy associated to the system is unbounded. In fact, it will be proved that the
energy will grow up as an exponential function as time goes to infinity, provided that the initial data are large enough.
The key ingredient in the proof is a method used in Vitillaro (Arch Ration Mech Anal 149:155–182, 1999) and developed in Said-Houari
(Diff Integr Equ 23(1–2):79–92, 2010) for a system of wave equations, with necessary modification imposed by the nature of
our problem. 相似文献
84.
Tao H Allison TK Wright TW Stooke AM Khurmi C van Tilborg J Liu Y Falcone RW Belkacem A Martinez TJ 《The Journal of chemical physics》2011,134(24):244306
Using a combined theoretical and experimental approach, we investigate the non-adiabatic dynamics of the prototypical ethylene (C(2)H(4)) molecule upon π → π? excitation. In this first part of a two part series, we focus on the lifetime of the excited electronic state. The femtosecond time-resolved photoelectron spectrum (TRPES) of ethylene is simulated based on our recent molecular dynamics simulation using the ab initio multiple spawning method with multi-state second order perturbation theory [H. Tao, B. G. Levine, and T. J. Martinez, J. Phys. Chem. A 113, 13656 (2009)]. We find excellent agreement between the TRPES calculation and the photoion signal observed in a pump-probe experiment using femtosecond vacuum ultraviolet (hν = 7.7 eV) pulses for both pump and probe. These results explain the apparent discrepancy over the excited state lifetime between theory and experiment that has existed for ten years, with experiments [e.g., P. Farmanara, V. Stert, and W. Radloff, Chem. Phys. Lett. 288, 518 (1998) and K. Kosma, S. A. Trushin, W. Fuss, and W. E. Schmid, J. Phys. Chem. A 112, 7514 (2008)] reporting much shorter lifetimes than predicted by theory. Investigation of the TRPES indicates that the fast decay of the photoion yield originates from both energetic and electronic factors, with the energetic factor playing a larger role in shaping the signal. 相似文献
85.
In this paper, we consider the Cauchy problem for a system of elastic solids with voids. First, we show that a linear porous dissipation leads to decay rates of regularity-loss type of the solution. We show some decay estimates for initial data in Hs(R)∩L1(R). Furthermore, we prove that by restricting the initial data to be in Hs(R)∩L1,γ(R) and γ∈[0,1], we can derive faster decay estimates of the solution. Second, we show that by adding a viscoelastic damping term, then we gain the regularity of the solution and obtain the optimal decay rate. 相似文献
86.
The goal of this work is to study a model of the strongly damped wave equation with dynamic boundary conditions and nonlinear boundary/interior sources and nonlinear boundary/interior damping. First, applying the nonlinear semigroup theory, we show the existence and uniqueness of local in time solutions. In addition, we show that in the strongly damped case solutions gain additional regularity for positive times t>0. Second, we show that under some restrictions on the initial data and if the interior source dominates the interior damping term and if the boundary source dominates the boundary damping, then the solution grows as an exponential function. Moreover, in the absence of the strong damping term, we prove that the solution ceases to exists and blows up in finite time. 相似文献
87.
Belkacem Sahli 《Applied Mathematics Letters》2012,25(1):77-80
The question of non-uniqueness in the integral formulation of an exterior boundary value problem in the elastic two-dimensional case has been resolved using the modified Green’s function technique. In this work, a new criterion of optimality based on the minimization of the norm of the kernel of the modified integral operator is established. 相似文献
88.
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