More accurate QM/MM MD technique based on ONIOM-XS method (called briefly as ONIOM-XS MD) has been applied for studying the solvation structure and dynamics of Na+ in weak H-bond liquid ammonia (NH3). By the ONIOM-XS MD technique, the system consists of a �high-level� QM region, which is treated by quantum mechanics, and the remaining �low-level� MM region described by classical MM force fields. In this study, all interactions within the QM region were treated at Hartree-Fock (HF) level of accuracy using double-? plus polarization basis set, while the interactions within the MM and between the QM and MM regions were described by means of pair potentials. The �structure-making� ability of Na+ in ordering its surrounding NH3 to form its specific complex will be compared to the characteristics of liquid NH3 treated by the same ONIOM-XS MD technique. The ONIOM-XS MD results clearly provide more insights into the solvation structure and dynamics of Na+ in liquid NH3. It is observed that Na+ can strongly order the local structure of its surrounding NH3 to form a well-defined Na+(NH3)5 complex. The average coordination number of 5.1 obtained by the present ONIOM-XS MD simulation is in good accord with the ND and XAS experiments, which reported the corresponding coordination numbers of 5.3 and 5.2, respectively.REFERENCES Hannongbua, S., Australian Journal of Chemistry., 1991 , 44, 447-456.Kerdcharoen, T., Journal of Physical Chemistry A., 2000 , 104, 7073-7078.Kerdcharoen, T. and Morokuma, K., Chemical Physics Letters., 2002 , 355, 257-262.Tongraar, A., Kerdcharoen, T. and Hannongbua, S., Journal of Physical Chemistry A., 2006 , 110, 4924-4929.

Solvation structure and dynamics of Na<sup>+</sup> in weak H-bond liquid ammonia studied by ONIOM-XS MD simulations

247th National Meeting (2014)

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Solvation structure and dynamics of Na+ in weak H-bond liquid ammonia studied by ONIOM-XS MD simulations

Solvation structure and dynamics of Na⁺ in weak H-bond liquid ammonia studied by ONIOM-XS MD simulations