title: Measuring acetic acid dimer modes by ultrafast time-domain Raman spectroscopy.
abstract: Acetic acid is capable of forming strong multiple hydrogen bonds and therefore different dimeric H-bonded structures in neat liquid phase and in solutions. The low frequency Raman spectra of acetic acid (neat, in aqueous solution and as a function of temperature) were obtained by ultrafast time and polarization resolved optical Kerr effect (OKE) measurements. Isotropic OKE measurements clearly reveal a specific totally symmetric mode related to the dimeric structure H-bond stretching mode. The effects of isotope substitution, water dilution and temperature on this mode were investigated. These results together with anisotropic OKE measurements and density functional theory calculations for a number of possible dimers provide strong evidence for the cyclic dimer structure being the main structure in liquid phase persisting down to acetic acid concentrations of 10 M. Some information about the dimer structure and concentration dependence was inferred.
authors.affiliation: School of Chemistry, University of East Anglia, Norwich NR4 7TJ, UK. iheisler@yahoo.com.br
authors.forename: Ismael A
authors.initials: IA
authors.lastname: Heisler
authors.forename: Kamila
authors.initials: K
authors.lastname: Mazur
authors.forename: Sayuri
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tominaga
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Meech
mesh_terms: D019342:Acetic Acid / Q000737:chemistry*; D017666:Deuterium Oxide / Q000737:chemistry; D019281:Dimerization; D006860:Hydrogen Bonding; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013997:Time Factors
chemical_list: D017666:Deuterium Oxide; D019342:Acetic Acid