Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (5): 829-835.doi: 10.3866/PKU.WHXB201503041


Excitation Spectra and Photodissociation Dynamics of the B2П State of the N2O+ Ion

SUN Zhong-Fa, GAO Zhi, WU Xiang-Kun, TANG Guo-Qiang, ZHOU Xiao-Guo, LIU Shi-Lin   

  1. Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2015-01-05 Revised:2015-03-03 Published:2015-05-08
  • Contact: ZHOU Xiao-Guo
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21373194) and National Key Basic Research Program of China (973) (2013CB834602).


N2O+ ions in the X2П(0,0,0) ground state were prepared by (3+1) resonance-enhanced multiphoton ionization (REMPI) of jet-cooled N2O molecules at 360.55 nm, and then photoexcited to various vibrational levels in the B2П state over a wavelength range of 243-278 nm, followed by dissociation. The photofragment excitation (PHOFEX) spectrum was recorded by measuring the intensity of NO+ ion fragments vs excitation wavelength. The rotational constants and spin-orbit coupling were obtained by fitting the rotational structures of the vibrational bands. Thus, the contributions of highly excited vibronic levels of A2Σ+ states were distinguished from the other bands, and the original band of B2П state was verified. The series of vibrational bands in the PHOFEX spectrum were assigned to the transition of B2П(v1,v2,v3) ←X2П. The average released kinetic energy of dissociation from the various B2П(v1,v2,v3) ionic states was obtained by fitting the spreading contour of the NO+ ion peak in time-of-flight mass spectra. Dissociation mechanisms of N2O+(B2П) were proposed with the aid of the theoretical potential energy surfaces of N2O+ ions.

Key words: N2O+ ion, Resonance enhanced multiphoton ionization, Vibrational spectroscopy, Time-of-flight mass spectrum, Photodissociation