Abstract
A wide range of density functional theory (DFT) methods (37 altogether), including pure, hybrid, range-separated hybrid, double-hybrid, and dispersion-corrected functionals, have been employed to compute the harmonic vibrational frequencies of eight small water clusters ranging in size from the dimer to four different isomers of the hexamer. These computed harmonic frequencies have been carefully compared to recently published benchmark values that are expected to be very close to the CCSD(T) complete basis set limit. Of the DFT methods examined here, ωB97 and ωB97X are the most consistently accurate, deviating from the reference values by less than 20 cm-1 on average and never more than 60 cm-1. The performance of double-hybrid methods including B2PLYP and mPW2-PLYP is only slightly better than more economical approaches, such as the M06-L pure functional and the M06-2X hybrid functional. Additionally, dispersion corrections offer very little improvement in computed frequencies.
Recommended Citation
J. C. Howard et al., "Assessing the Accuracy of Some Popular DFT Methods for Computing Harmonic Vibrational Frequencies of Water Clusters," Journal of Chemical Physics, vol. 143, no. 21, article no. 214103, American Institute of Physics, Dec 2015.
The definitive version is available at https://doi.org/10.1063/1.4936654
Department(s)
Chemistry
Publication Status
Open Access
International Standard Serial Number (ISSN)
1089-7690; 0021-9606
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2024 American Institute of Physics, All rights reserved.
Publication Date
07 Dec 2015
Comments
National Science Foundation, Grant CHE-1338056