ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Clusters of methanol and ethanol formed above neat liquid samples were entrained in a supersonic jet of helium and probed in the expansion using 118 nm vacuum ultraviolet laser single-photon ionization/time-of-flight (TOF) mass spectrometry. Almost every cluster ion observed in the TOF mass spectra could be represented by the formula H(ROH)n+, where R=CH3 or C2H5, and n=1–5. Formation of these species is attributed to a well-established ionization pathway where each protonated (n−1)-mer originates from its n-mer neutral parent. Signals in the TOF mass spectra due to the protonated trimers H(CH3OH)3+ and H(CH3CH2OH)3+ were found to be the most intense and provides direct evidence that these particular cluster ions are "magic-number" structures. The possible relationships between the observed ion data and the neutral cluster vapor phase distributions are discussed. In this context, methanol and ethanol vapor cluster distributions at 298.15 K and at several pressures≥the equilibrium vapor pressure were computed using the grand canonical Monte Carlo and molecular dynamics techniques. Lastly, differences between these experiments and the results of bimolecular reaction studies are discussed. © 2002 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1466467
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