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Two Different Models to Predict Ionic‐Liquid Diffraction Patterns: Fixed‐Charge versus Polarizable Potentials
Author(s) -
Campetella Marco,
Gontrani Lorenzo,
Leonelli Francesca,
Bencivenni Luigi,
Caminiti Ruggero
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402577
Subject(s) - polarizability , diffraction , force field (fiction) , chemistry , multipole expansion , molecular dynamics , field (mathematics) , scattering , molecular physics , spectral line , ionic liquid , chemical physics , computational chemistry , analytical chemistry (journal) , atomic physics , physics , molecule , optics , quantum mechanics , mathematics , organic chemistry , catalysis , pure mathematics
This study reports the performance of classical molecular dynamics (MD) in predicting the X‐ray diffraction patterns of butylammonium nitrate (BAN) and two derivatives, 4‐hydroxybutan‐1‐ammonium nitrate (4‐HOBAN) and 4‐methoxybutan‐1‐ammonium nitrate (4‐MeOBAN). The structure functions and radial distribution functions obtained from energy‐dispersive X‐ray diffraction spectra, recorded newly for BAN and for the first time for 4‐MeOBAN and 4‐HOBAN, are compared with the corresponding quantities calculated from MD trajectories, to access information on the morphology of these liquids. The different behavior of two force fields, a polarizable multipole force field and a fixed‐charge one supplemented by an explicit three‐body term, is shown. The three‐body force field proves to be superior in reproducing the intermediate q range, for which the polarizable force field gives the wrong peak position and intensities. In addition, both models can correctly account for the presence or absence of a low q peak in the scattering patterns.