Pressure broadening in the oxygen b1Σg+(υ′=1)←X3Σg-(υ"=0) band measured by cavity ring-down spectroscopy

We have measured coefficients for pressure broadening of the oxygen b(1) Sigma(g)(+)(upsilon' = 1) <-- X-3 Sigma(g)(-)(upsilon(n) = 0) band at 688 nm by N-2 using cavity ring-down spectroscopy. There is a noticeable dependence on rotational quantum number, consistent with significant anisotropy in the N-2-O-2 intermolecular potential. The results also suggest that pressure broadening coefficients may depend on the collider and on the vibrational quantum number of the absorber. (C) 1998 Elsevier Science B.V.