title: Novel SCS-IL-MP2 and SOS-IL-MP2 Methods for Accurate Energetics of Large-Scale Ionic Liquid Clusters.
abstract: Accurate energetics of intermolecular interactions in condensed systems are challenging to predict using highly correlated quantum chemical methods due to their great computational expense. Semi-Coulomb systems such as ionic liquids, in which electrostatic, dispersion, and induction forces are equally important, represent a further challenge for wave function-based methods. Here, the application of our recently developed SCS-IL-MP2 and SOS-IL-MP2 methods is reported for ionic liquid clusters of two and four ion pairs. Correlation interaction energies were found to be within 1.5 kJ mol(-1), on average, per ion pair of the CCSD(T)/CBS benchmark, thus introducing a marked improvement by a factor of 4 to conventional MP2 within the complete basis set. The fragment molecular orbital (FMO) approach in combination with both SCS-IL-MP2 and SOS-IL-MP2 has been shown to provide a reliable and computationally inexpensive alternative to CCSD(T)/CBS for large-scale calculations of ionic liquids, thus paving the way toward feasible ab initio molecular dynamics and development of reliable force fields for these condensed systems.
authors.affiliation: School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, 3800 VIC, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Rigby
authors.affiliation: School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, 3800 VIC, Australia.
authors.forename: Santiago
authors.initials: S
authors.lastname: Barrera Acevedo
authors.affiliation: School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, 3800 VIC, Australia.
authors.forename: Ekaterina I
authors.initials: EI
authors.lastname: Izgorodina
mesh_terms: D052578:Ionic Liquids / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008956:Models, Chemical; D013816:Thermodynamics
chemical_list: D052578:Ionic Liquids; D007477:Ions