title: Assessment of CCSD(T)-F12 Approximations and Basis Sets for Harmonic Vibrational Frequencies.
abstract: We consider basis set convergence and the effect of various approximations to CCSD(T)-F12 for a representative sample of harmonic frequencies (the HFREQ2014 set). CCSD(T*)(F12*)/cc-pVDZ-F12 offers a particularly favorable compromise between accuracy and computational cost: its RMSD <3 cm(-1) from the valence CCSD(T) limit is actually less than the remaining discrepancy with the experimental value at the valence CCSD(T) limit (about 5 cm(-1) RMSD). CCSD(T)-F12a and CCSD(T)-F12b appear to benefit from error compensation between CCSD and (T).
authors.affiliation: Department of Organic Chemistry, Weizmann Institute of Science , 76100 Reh̲ovot, Israel.
authors.forename: Jan M L
authors.initials: JM
authors.lastname: Martin
authors.affiliation: Department of Organic Chemistry, Weizmann Institute of Science , 76100 Reh̲ovot, Israel.
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Kesharwani