Sm. Newman et al., Temperature and pressure dependence of line widths and integrated absorption intensities for the O-2 a(1)Delta(g)-X-3 Sigma(-)(g) (0,0) transition, J PHYS CH A, 104(42), 2000, pp. 9467-9480
The electric-dipole forbidden a(1)Delta (g) - X(3)Sigma (-)(g) (0,0) band o
f gas-phase O-2 has been studied in absorption at wavelengths around 1.27 m
um using Fourier transform spectroscopy and a long-path absorption cell. Ex
periments were conducted at temperatures of 294, 243, and 200 K and at pres
sures in the range 140-750 Torr. Both pure O-2 and a mixture of 21% O-2/79%
N-2 were studied, and line widths, integrated line intensities, and integr
ated absorption intensities (AIs) for the (0,0) vibrational band were measu
red. Integrated AIs were found to be independent of temperature, pressure,
and gas composition, and the recommended value for the vibrational band fro
m the current study is S-int = 3.210(15) x 10(-24) cm molecule(-1) (1 sigma
error) for pure O-16(2), corresponding to an Einstein A-coefficient of A =
2.256(10) x 10(-4) s(-1). The effect of including other oxygen isotopomers
is to increase the integrated AI value for this origin band to S-int = 3.2
26(15) x 10(-24) cm molecule(-1) Widths of individual spectroscopic lines d
ecrease with increasing molecular rotational quantum number. The temperatur
e dependence of Lorentzian line width components, gamma (T) (fwhm), is well
represented by the expression gamma (T) = gamma (294K)(T/294 K)(-0.85). Th
e effects of pressure broadening of lines by N-2 are indistinguishable from
those for pure O-2 at the same temperature and pressure.