The intermediate scattering function for quasi-elastic scattering in the\n presence of memory friction

Le résumé fourni par la source

We derive an analytical expression for the intermediate scattering function\nof a particle on a flat surface obeying the Generalised Langevin Equation, with\nexponential memory friction. Numerical simulations based on an extended phase\nspace method confirm the analytical results. The simulated trajectories provide\nqualitative insight into the effect that introducing a finite memory timescale\nhas on the analytical line shapes. The relative amplitude of the long-time\nexponential tail of the line shape is suppressed, but its decay rate is\nunchanged, reflecting the fact that the cutoff frequency of the exponential\nkernel affects short-time correlations but not the diffusion coefficient which\nis defined in terms of a long-time limit. The exponential sensitivity of the\nrelative amplitudes to the decay time of the chosen memory kernel is a very\nstrong indicator for the prospect of inferring a friction kernel and the\nphysical insights from experimentally measured intermediate scattering\nfunctions.\n

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