Knowledge Bank

Preliminary results are presented on positive ion fragmentation patterns of acetaldehyde produced by multiphoton ionization (MPI) in the ion collection region of a quadrupole mass spectrometer. Fragment ion production ratios, obtained with unit mass resolution, are seen to vary with both laser intensity and excitation wavelength. Comparison is made to conventional MPI spectra of acetaldehyde obtained with a parallel plate cell, and vibrational assignments are made for the 2-photon resonant intermediate states. Possible mechanisms for fragmentation are discussed.