Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (08): 1797-1802.doi: 10.3866/PKU.WHXB20110717


Dissociation Dynamics of O+ Formation Channels from Vibrational State-Selected NO2+ at e3B2 State

NIU Ming-Li1, SONG Lei1, TANG Xiao-Feng1, ZHOU Xiao-Guo1, LIU Shi-Lin1, LIU Fu-Yi2, SHAN Xiao-Bin2, SHENG Liu-Si2   

  1. 1. Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China;
    2. National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029, P. R. China
  • Received:2011-02-28 Revised:2010-04-06 Published:2011-07-19
  • Contact: ZHOU Xiao-Guo
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10979042, 21073173) and National Key Basic Research Program of China (973) (2007CB815204).


The dissociation dynamics of vibrational state-selected NO2+(e3B2) was investigated using threshold photoelectron-photoion coincidence velocity imaging and photoionization by synchrotron radiation. The vibrational resolution threshold photoelectron spectrum of NO2+ (e3B2) was recorded in the energy range of 18.8-19.2 eV and was consistent with previous measurements. Furthermore, the coincident velocity images of the O+ fragments that dissociated from the (0,0,0) and (1,0,0) vibronic levels of NO2+ (e3B2) showed a multi-ring structure, indicating that O+ fragments with different speeds were produced during dissociation as well as corresponding NO molecules with different internal energy distributions. The total kinetic energy released distributions and the angular distributions of O+ during dissociation were obtained subsequently from the images. The internal energy distributions of the NO (X2Π) fragments that dissociated from the two vibrational states of NO2+(e3B2) were very similar and consisted of 3-5 dominant populated vibronic levels. The available energy released from dissociation was found to be almost evenly distributed between the kinetic and internal energies of the fragments and, specifically, a total kinetic energy of 52% and an internal energy of 48% were obtained. In addition, the anisotropy parameter, β, of the O+ fragments was about 0.3 and was hardly dependent on the vibrational quantum number of the NO(X2Π) fragment.

Key words: Dissociation dynamics, Photoionization, Threshold photoelectron spectrum, Photoelectron-photoion coincidence, Velocity map imaging