Related Experiment Video
Updated: Jun 18, 2026

Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation
Published on: October 30, 2012
Intermolecular proton-transfer in acetic acid clusters induced by vacuum-ultraviolet photoionization
Keisuke Ohta1, Yoshiyuki Matsuda, Naohiko Mikami
1Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki-Aoba, Aoba-ku, Sendai 980-8578, Japan.
Abstract:
Infrared (IR) spectroscopy based on vacuum-ultraviolet one-photon ionization detection was carried out to investigate geometric structures of neutral and cationic clusters of acetic acid: (CH(3)COOH)(2), CH(3)COOH-CH(3)OH, and CH(3)COOH-H(2)O. All the neutral clusters have cyclic-type intermolecular structures, in which acetic acid and solvent molecules act as both hydrogen donors and acceptors, and two hydrogen-bonds are formed. On the other hand, (CH(3)COOH)(2) (+) and (CH(3)COOH-CH(3)OH)(+) form proton-transferred structures, where the acetic acid moiety donates the proton to the counter molecule. (CH(3)COOH-H(2)O)(+) has a non-proton-transferred structure, where CH(3)COOH(+) and H(2)O are hydrogen-bonded. The origin of these structural differences among the cluster cations is discussed with the relative sizes of the proton affinities of the cluster components and the potential energy curves along the proton-transfer coordinate.
Related Concept Videos
IR and UV–Vis Spectroscopy of Carboxylic Acids
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
Polyprotic Acids
Brønsted-Lowry Acids and Bases
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
¹H NMR of Labile Protons: Temporal Resolution
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
Leveling Effect

