Acta Phys. -Chim. Sin. ›› 1996, Vol. 12 ›› Issue (11): 981-985.doi: 10.3866/PKU.WHXB19961105

• ARTICLE • Previous Articles     Next Articles

Study of the Multiphoton Ionization Mass Spectra of Methylamine

 Liu Xiao-Jun,Zhang Bing,Fang Li,Guo Wen-Yue,Zhou Jin-Gang,Cai Ji-Ye,Lu Yi-Qun,Zhou Shi-Kang   

  1. Laser Spectroscopy Laboratory,Anhui Institute of Optics and Fine Mechanics,Academia Sinica,Hefei 230031
  • Received:1996-05-10 Revised:1996-07-10 Published:1996-11-15
  • Contact: Liu Xiao-Jun


Multiphoton ionization-dissociation process of Methylamine Molecules is studied using Time-Of-Flight mass spectrometer with a pulsed dye laser. Four ion peaks observed under different laser wavelength and laser power are assigned to CH3NH2+、CH2NH2+、 CHNH2+ (CH2NH+) and CHNH+. Based on the experimental results, the Multiphoton lonization and Dissociation(MPID) mechanism of CH3NH2 are discribed:CH3NH2 molecule is ionized to generate CH3NH2+ via 2+2 photon(two photon resonant excitation and two photon ionization)process. CH3NH2+ dissociate to produce CH2NH2+. CHNH2+(CH2NH+) and CHNH+ are generated by the consequent dissociation of CH2NH2+. The experimental results indicate that the dissociation rate constant of CH3NH2+ decreases as laser wavelength increases.

Key words: Methylamine, Multiphoton ionization and dissociation(MPID), Time-of-flight mass spectrometer(TOF-MS)