J. Coleman Howard

TL;DR: This comparison reveals that it is far more challenging to converge harmonic vibrational frequencies for the bound OH stretching modes in these (H2O)n clusters to the CCSD(T) CBS limit than the free OH stretches, the n intramonomer HOH bending modes and even the 6n - 6 intermonomer modes.

TL;DR: This work presents a systematic investigation into the basis set convergence of harmonic vibrational frequencies of (H2O)2 and (HF)2 computed with second-order Møller-Plesset perturbation theory and the coupled-cluster singles and doubles method with perturbative connected triples, CCSD(T), while employing correlation-consistent basis sets as large as aug-cc-pV6Z.

TL;DR: A review of the recent and exciting work in this area and an overview of popular strategies for generating reliable properties and benchmark quality energetics for water clusters with correlated wavefunction methods can be found in this paper.

TL;DR: The performance of double-hybrid methods including B2PLYP and mPW2-PLYP is only slightly better than more economical approaches, and dispersion corrections offer very little improvement in computed frequencies.

TL;DR: An efficient method for reproducing CCSD(T) optimized geometries and harmonic vibrational frequencies for molecular clusters with the N-body:Many-body QM:QM technique, well-suited for parallelization on relatively modest computational hardware.