Optimized molecular reconstruction procedure combining hybrid reverse Monte Carlo and molecular dynamics

C Bousige and A Botan and FJ Ulm and RJM Pellenq and B Coasne, JOURNAL OF CHEMICAL PHYSICS, 142, 114112 (2015).

DOI: 10.1063/1.4914921

We report an efficient atom-scale reconstruction method that consists of combining the Hybrid Reverse Monte Carlo algorithm (HRMC) with Molecular Dynamics (MD) in the framework of a simulated annealing technique. In the spirit of the experimentally constrained molecular relaxation technique Biswas et al., Phys. Rev. B 69, 195207 (2004), this modified procedure offers a refined strategy in the field of reconstruction techniques, with special interest for heterogeneous and disordered solids such as amorphous porous materials. While the HRMC method generates physical structures, thanks to the use of energy penalties, the combination with MD makes the method at least one order of magnitude faster than HRMC simulations to obtain structures of similar quality. Furthermore, in order to ensure the transferability of this technique, we provide rational arguments to select the various input parameters such as the relative weight. of the energy penalty with respect to the structure optimization. By applying the method to disordered porous carbons, we show that adsorption properties provide data to test the global texture of the reconstructed sample but are only weakly sensitive to the presence of defects. In contrast, the vibrational properties such as the phonon density of states are found to be very sensitive to the local structure of the sample. (C) 2015 AIP Publishing LLC.

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