Premium
A systematic benchmarking of computational vibrational spectroscopy with DFTB3: Normal mode analysis and fast Fourier transform dipole autocorrelation function
Author(s) -
Inakollu V. S. Sandeep,
Yu Haibo
Publication year - 2018
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.25390
Subject(s) - anharmonicity , autocorrelation , fourier transform , chemistry , dipole , molecular vibration , infrared spectroscopy , spectroscopy , spectral line , function (biology) , fourier transform spectroscopy , infrared , molecular physics , molecule , computational chemistry , physics , optics , mathematics , quantum mechanics , statistics , evolutionary biology , organic chemistry , biology
Computational vibrational spectroscopy serves as an important tool in the interpretation of experimental infrared (IR) spectra. In this article, we present a systematic benchmarking study of DFTB3 with two different computational vibrational spectroscopic methods, based on either normal mode analysis (NMA) or fast Fourier transform dipole autocorrelation function (FT‐DAC). The results were compared with experimental data and theoretical calculations with B3LYP/cc‐pVTZ. The empirical scaling factors for DFTB3/NMA, DFTB3‐freq/NMA, and DFTB3/FT‐DAC methods are 0.9993, 1.0059, and 0.9982, respectively. We also demonstrate the significance of anharmonicity and conformational sampling in vibrational spectroscopic calculations on flexible molecules. As expected, DFTB3/FT‐DAC predicted the anharmonic vibrational peaks more accurately than DFTB3/NMA and NMA spectra are highly dependent on the initial structures. The potential limitations of DFTB3 for vibrational spectroscopic calculations and the challenges in assigning the FT‐DAC spectral peaks were noted. DFTB3/FT‐DAC is expected to serve as a promising technique in computational spectroscopy in complex biomolecular systems. © 2018 Wiley Periodicals, Inc.