Vibrational spectroscopy and molecular dynamics simulation of choline oxyanions salts

Ícaro F.T. de Souza, Vitor H. Paschoal, Kalil Bernardino, Thamires A. Lima, Luke L. Daemen, Y Z, Mauro C.C. Ribeiro

Research output: Contribution to journalArticlepeer-review


The structure of choline salts containing the anions acetate, [Chol][Ac], and dihydrogen phosphate, [Chol][DHP], were investigated by infrared, Raman, and inelastic neutron scattering (INS). The chosen systems allow for the comparison of structural effects related to the bond acceptor characteristic of [Ac] and the simultaneous acceptor and donor characteristics of [DHP] in forming hydrogen bonds (H-bond) in salts of [Chol], which is itself prone to forming H-bonds. Different computational tools were used for the analysis of different spectral ranges. The calculation of the low-frequency range of Raman and INS spectra of the crystalline phases at low-temperatures by solid state DFPT (density functional perturbation theory) unveils the coupling between vibrations of the H-bonds and intramolecular modes. Changes observed in the spectral pattern of lattice and [DHP] modes upon heating crystalline [Chol][DHP] are analogous to the ferroelectric–paraelectric phase transition known in the potassium salt of [DHP]. The fingerprint region of the vibrational spectra provides information concerning the [Chol] conformation in the solid phase (gauche in [Chol][Ac] and anti in [Chol][DHP]) and in aqueous solution. DFT calculations of ionic pairs and ionic clusters unveil the interplay between [Chol] conformation and the [DHP] ability to form H-bonded dimers of anions. The high-frequency spectral range and the structures driven by H-bonds are discussed using classical molecular dynamics (MD) simulations. The MD simulations of aqueous solutions highlight the strong anion-cation H-bond in [Chol][Ac], in contrast to the strong anion–anion H-bond in [Chol][DHP] due to occurrence of dimers and larger clusters of [DHP].

Original languageEnglish (US)
Article number117100
JournalJournal of Molecular Liquids
StatePublished - Oct 15 2021


  • Choline
  • Density functional perturbation theory
  • Inelastic Neutron Scattering
  • Infrared
  • Molecular dynamics
  • Raman

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry


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