Hydrogen bonding in the ethanol-water dimer.
We report the first rotational spectrum of the ground state of the isolated ethanol-water dimer using chirped-pulse Fourier transform microwave spectroscopy between 8-18 GHz. With the aid of isotopic substitutions, and ab initio calculations, we identify the measured conformer as a water-donor/ethanol-acceptor structure. Ethanol is found to be in the gauche conformation, while the monomer distances and orientations likely reflect a cooperation between the strong (O-HO) and weak (C-HO) hydrogen bonds that stabilizes the measured conformer. No other conformers were assigned in an argon expansion, confirming that this is the ground-state structure. This result is consistent with previous vibrationally-resolved Raman and infrared work, but sheds additional light on the structure, due to the specificity of rotational spectroscopy.
Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA. gab@gps.caltech.edu.
Ian A
IA
Finneran
P Brandon
PB
Carroll
Marco A
MA
Allodi
Geoffrey A
GA
Blake
D019281:Dimerization; D000431:Ethanol / Q000737:chemistry*; D006860:Hydrogen Bonding; D011789:Quantum Theory; D014867:Water / Q000737:chemistry*
D014867:Water; D000431:Ethanol