New scale factors for harmonic vibrational frequencies using the B3LYP density functional method with the triple-xi basis set 6-311+G(d,p)

Summary, in English

We have calculated optimal frequency scaling factors for the B3LYP/ 6-311+G(d,p) method for fundamental vibrational frequencies on the basis of a set of 125 molecules. Using the new scaling factor, the vibrational frequencies calculated with the triple-zeta basis set 6-311+G(d,p) give significantly better accuracy than those calculated with the double-zeta 6-31G(d) basis set. Scale factors were also determined for low-frequency vibrations using the molecular set of 125 molecules and for zero-point energies using a smaller set of 40 molecules. We have studied the effect on the calculated vibrational frequencies for various combinations of diffuse and polarization functions added to the triple-zeta 6-311G basis set. The 6-311+G(d,p) basis set is found to give almost converged frequencies for most molecules, and we conclude that our optimum scaling factors are valid for the basis sets 6-311 G(d,p) to 6-311++G(3df,3pd). The new scale factors are 0.9679 for vibrational frequencies, 1.0100 for low-frequency vibrations, and 0.9877 for zero-point vibrational energies.

• Author: M P Andersson; Per Uvdal
• Department/s: Chemical Physics
• Publishing year: 2005
• Language: English
• Pages: 2937-2941
• Publication/Series: The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
• Volume: 109
• Issue: 12
• Links: http://dx.doi.org/10.1021/jp045733a
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Atom and Molecular Physics and Optics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1520-5215