TY - JOUR
T1 - Comparative very-high-resolution VUV spectroscopy
T2 - Laser spectroscopy of O2
AU - Lewis, Brenton R.
AU - Gibson, S. T.
AU - Baldwin, K. G.H.
AU - Dooley, P. M.
AU - Waring, K.
PY - 2002/2
Y1 - 2002/2
N2 - Despite their importance to the photochemistry of the terrestrial atmosphere, and many experimental studies, previous characterization of the Schumann-Runge (SR) bands of O2, B3∑ū ← X 3∑ḡ (υ, 0) (1750-2050 Å) has been limited by poor experimental resolution. In addition, our understanding of the SR spectrum is incomplete, many rovibrational transitions in the perturbed region of the spectrum [B(υ > 15)] remaining unassigned. We review new very-high-resolution measurements of the O2 photoabsorption cross section in the SR bands. Tunable, narrow-bandwidth background vacuum-ultraviolet (VUV) radiation for the measurements (∼ 7 × 105 resolving power) was generated by the two-photon-resonant difference-frequency four-wave mixing in Xe of excimer-pumped dye-laser radiation. With the aid of these cross-section measurements, rovibrational and line-shape analyses have led to new insights into the molecular structure and predissociation dynamics of O2. The current VUV laser-spectroscopic measurements are shown to compare favourably with results from two other very-high-resolution experimental techniques, namely laser-induced fluorescence spectroscopy and VUV Fourier-transform spectroscopy, the latter performed using a synchrotron source.
AB - Despite their importance to the photochemistry of the terrestrial atmosphere, and many experimental studies, previous characterization of the Schumann-Runge (SR) bands of O2, B3∑ū ← X 3∑ḡ (υ, 0) (1750-2050 Å) has been limited by poor experimental resolution. In addition, our understanding of the SR spectrum is incomplete, many rovibrational transitions in the perturbed region of the spectrum [B(υ > 15)] remaining unassigned. We review new very-high-resolution measurements of the O2 photoabsorption cross section in the SR bands. Tunable, narrow-bandwidth background vacuum-ultraviolet (VUV) radiation for the measurements (∼ 7 × 105 resolving power) was generated by the two-photon-resonant difference-frequency four-wave mixing in Xe of excimer-pumped dye-laser radiation. With the aid of these cross-section measurements, rovibrational and line-shape analyses have led to new insights into the molecular structure and predissociation dynamics of O2. The current VUV laser-spectroscopic measurements are shown to compare favourably with results from two other very-high-resolution experimental techniques, namely laser-induced fluorescence spectroscopy and VUV Fourier-transform spectroscopy, the latter performed using a synchrotron source.
UR - http://www.scopus.com/inward/record.url?scp=0036462874&partnerID=8YFLogxK
U2 - 10.1142/S0218625X02001690
DO - 10.1142/S0218625X02001690
M3 - Article
SN - 0218-625X
VL - 9
SP - 31
EP - 38
JO - Surface Review and Letters
JF - Surface Review and Letters
IS - 1
ER -