Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (04): 963-970.doi: 10.3866/PKU.WHXB201202162

• PHOTOCHEMISTRY AND RADIATION CHEMISTRY • Previous Articles     Next Articles

Photodissociation Spectra of OCS+ via A2ПX2П Transitions

ZHOU Dan-Na, CHEN Lin, WU Dan, ZHANG Li-Min   

  1. Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2011-12-05 Revised:2012-01-31 Published:2012-03-21
  • Contact: ZHANG Li-Min
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21073177).

Abstract: In the wavelength range 260-325 nm, we obtained mass-resolved dissociation spectra of OCS+ via A2П3/2X2П3/2 (000) and A2П1/2X2П1/2 (000, 001) transitions by preparing OCS+ (X2П) ions via [3+1] resonance enhanced multiphoton ionization (REMPI) of OCS molecules at 423, 420, 412.2, and 408.4 nm. The mass-resolved dissociation spectra of OCS+ via A2П1/2X2П1/2 (001) were observed for the first time. The spectroscopic constants T0=31411.3 cm-1 and v1=814.3 cm-1 for the OCS+ (A2П3/2) state were deduced from the A2П3/2X2П3/2 (000) photodissociation spectra, and the spectroscopic constants v1=816 cm-1, v2=(380.4± 2.8) cm-1, and v3=(2052.7±5.1) cm-1 for the OCS+ (A2П1/2) state were deduced from the A2П1/2X2П1/2 (000) spectra. The spectroscopic constant v1=786.4 cm-1 was deduced from the A2П1/2X2П1/2 (001) photodissociation spectra. The results show that the C-O stretching mode excitation of X2П1/2 can affect the C-S stretching mode vibration of the A2П1/2 state via A2П1/2X2П1/2 (001) transitions. Bands involving the bending v2 mode excitation of A2П, such as A2П1/2 (020, 120, 021, …), were observed for the A2П1/2X2П1/2 (000, 001) transitions, but were not observed for the A2П3/21υ2υ3) ←X2П3/2 (000) transitions in the photodissociation spectra. The reason for this dependence of the bending v2 mode excitation of A2П on the spin-orbit splitting of the 2П state can be attributed to the Fermi resonance and Renner-Teller effect of OCS+ (A2П).

Key words: OCS+, Photodissociation, Bending mode excitation, Photofragment excitation spectrum