Abstract: Resonant twophoton ionization spectra of S1←S0 transition in complex oxylene…NH3(ND3) in supersonic molecular beam are observed using resonant two photon ionization,together with time of flight mass spectrometry. The spectra exhibit rich information on the complex intermolecular vdW vibrational modes.We have tentatively assigned all the observed spectral features.By analyzing the spectra,the stretching vibrational frequencies and two bending vibrational frequencies of the the complex are obtained.The structure of the complex has been obtained by abinitio computation method.

Key words: Spectrum of resonant twophoton ionization, van der Waals vibrations between molecules