Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (12): 2749-2754.doi: 10.3866/PKU.WHXB20112749


Ionization and Dissociation of Methyl Chloride in an Excitation Energy Range of 13-17 eV

WU Man-Man, TANG Xiao-Feng, NIU Ming-Li, ZHOU Xiao-Guo, DAI Jing-Hua, LIU Shi-Lin   

  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
  • Received:2011-09-21 Revised:2011-10-09 Published:2011-11-25
  • 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).

Abstract: Using threshold photoelectron-photoion coincidence time-of-flight mass spectrometry, the photoionization and photodissociation of methyl chloride in the excitation energy range of 13-17 eV were investigated. CH3Cl+ ions in the A2A1 and B2E excited states were generated, both of which were completely dissociative. CH3+ fragments were mainly produced while CH2Cl+ fragment ions were observed as well. By fitting the time-of-flight profile the kinetic energy released distributions of CH3+ during the dissociation of the energy-selected CH3Cl+ ions were obtained. The dissociation of the CH3Cl+ (A2A1) ion followed rapid direct fragmentation while that of the B2E state showed statistical dissociation. Moreover, with the aid of the calculated potential energy surface the CH2Cl + fragment ions observed in the A2A1 state were generated from the statistical dissociation of the high vibrational excited CH3Cl+ (X2E) ions produced by the autoionization of the CH3Cl molecule.

Key words: Methyl chloride, Photoionization, Photodissociation, Time-of-flight mass spectroscopy, Potential energy surface