title: Microsolvation of protonated methane: structures and energetics of CH5(+)(H2)n.
abstract: Effects of microsolvating CH(5)(+) with up to four H(2) molecules have been investigated in terms of structures and energies. For the smaller complexes, benchmark calculations have been carried out using MP2 and CCSD(T) with basis sets up to aug-cc-pV5Z quality and energies have been extrapolated to the infinite basis set limit. It is found that MP2 calculations using the aug-cc-pVQZ basis set or better yield robust reference data for both structures and energies. More than 30 stationary points including minima and first-order as well as second-order stationary points have been characterized by this method and are discussed in terms of solvation motifs. Finally, the performance of several density functionals has been assessed for this very demanding case. Popular GGA functionals such as BLYP and PBE fail, whereas the TPSS meta-GGA functional captures many structural and energetic aspects of microsolvation satisfactorily.
authors.affiliation: Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany. alexander.witt@theochem.rub.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Witt
authors.forename: Sergei D
authors.initials: SD
authors.lastname: Ivanov
authors.forename: Harald
authors.initials: H
authors.lastname: Forbert
authors.forename: Dominik
authors.initials: D
authors.lastname: Marx