The ultraviolet photodissociation dynamics of IBr studied using state-selective translational spectroscopy Academic Article uri icon


  • We have investigated the ultraviolet photodissociation of IBr using core-sampled state-selective ion time-of-flight mass spectrometry on the iodine and bromine atom products. The branching ratios and anisotropy parameters were determined for the I(2P3/2)+Br(2P3/2), I(2P3/2)+Br(2P1/2), and I(2P1/2)+Br(2P3/2) channels at 248, 267, and 304 nm. We find no evidence for the I(2P1/2)+Br(2P1/2) channel at any wavelength. The results provide information on the relative transition probabilities for the 31(2341), 30+(2341), and 11(2341) excited states in the absorption band centered at 270 nm. We have further evaluated the nonadiabatic curve crossing probability for the avoided crossing between the 30+(2341) and 3-0+(2422) states over a range of wavelengths from 250 to 270 nm. The wavelength-dependent curve crossing probability for the avoided crossing is modeled using one-dimensional Landau-Zener theory in order to estimate the location of the avoided crossing and the splitting between adiabats. A comparison with recent work at 267 and 304 nm and analogous interhalogen molecules is also provided.

published proceedings


author list (cited authors)

  • McGivern, W. S., Li, R. J., Zou, P., Nguyen, T., & North, S. W.

citation count

  • 10

complete list of authors

  • McGivern, WS||Li, RJ||Zou, P||Nguyen, T||North, SW

publication date

  • November 1999