Abstract: Alcohol-water complex clusters were studied by using multiphoton ionization technique and time-of-flight mass spectrometer. Laser with 355nm wavelengths were used as ionized source, protonated cluster ions (ROH)n(H2O)H+ and (ROH)nH+ were observed where the R=CH3 or C2H5. The formation of (ROH)n(H2O)H+ is mainly through proton transfer reaction intra alcohol-water clusters ions after laser multiphoton ionization. Some possible geometric structures of (CH3OH)n(H2O)H+ with relatively small sizes were guessed using ab initio calculation method. The structures show that the (CH3OH)H+ trends as the ion’s center, and then it combines with other methanol or ethanol molecule to form the final stable complex cluster ions.

Key words: spectroscopy, protonated clusters, multiphoton ionization, time-of-flight mass spectrum