Vibrational spectra of crystalline powder of four isotopologues of formic acid (HCOOH, HCOOD, DCOOH, DCOOD) and of acetic acid (CH3COOH, CH3COOD, CD3COOH, CD3COOD) were recorded at 20 K by inelastic neutron scattering. These spectra are compared with computed spectra based on harmonic force fields derived from periodic density functional theory (DFT) calculations. The assignment of all internal vibrations is obvious from the spectral changes under isotopic substitution. Discrepancies between calculation and experiment expose the over evaluation of the strength of the hydrogen bond by these standard DFT calculations. © 2008 Elsevier B.V. All rights reserved.
Johnson, M. R., & Trommsdorff, H. P. (2009). Vibrational spectra of crystalline formic and acetic acid isotopologues by inelastic neutron scattering and numerical simulations. Chemical Physics, 355(2–3), 118–122. https://doi.org/10.1016/j.chemphys.2008.11.012