Acta Phys. -Chim. Sin. ›› 1995, Vol. 11 ›› Issue (01): 87-91.doi: 10.3866/PKU.WHXB19950118

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Laser Dissociation of Methyl Nitrite Around 440nm

Li Hai-Yang, Mo Hua-Ping, Bai Ji-Ling, Dai Dong-Xu   

  1. State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Physical Chemistry,Chinese Academy of Sciences,Dalian 116023
  • Received:1993-11-19 Revised:1994-02-22 Published:1995-01-15
  • Contact: Li Hai-Yang

Abstract:

The collision-free multiphoton ionization and dissociation of jet cooling methyl nitrite (CH3ONO) were studied by using intense dye laser around 440nm. NO+ ion peak in the TOF mass spectrum was obtained under different accelerating electric field and different angle (χ) between laser polarization plane and the axis of the flight tube. NO+ peak is broadened when NO comes from the dissociation of CH3ONO and this broadening becomes more apparent under lower accelerating electric field. NO+ peak shape is also influenced by the property of laser polarization. If the accelerating electric field is low enough, there are three peaks when χ=0℃ and only one peak when χ=90℃. These phennomena can be explained by CH3ONO’s two-photon transition from S0 to S2 repulsive state. NO thus produced has a large velocity parallel to the laser polarization plane.

Key words: Methyl nitrite, Multphoton ionization, Photofragmentation mechanism, Time of flight mass spectrometer