Coefficients of absorption for the O2 Schumann-Runge continuum have been measured in the range 1270 Å ↔ 1745 Å. For the measurement, a microsecond flashing source with continuous spectral energy distribution and photographic detection techniques have been utilized. In previous measurements, H2 discharges had been used almost exclusively. Three independent determinations by photographic photometry had given maximum coefficients of absorption between 460 cm-1 and 490 cm-1 (STP), whereas three independent photoelectric investigations yielded values between 390 cm-1 and 403 cm-1 the accuracy of the latter were estimated to be 5%–10%. Similar disagreement existed on the continuum oscillator strength. Our determination yields, for the maximum coefficient of absorption, 382 cm-1±10% and ƒ= 0.156, which is in good agreement with photoelectric measurements. Therefore, the formerly indicated discrepancy between photographic and photoelectric photometric techniques no longer exists.
R. GOLDSTEIN and F. N. MASTRUP, "Absorption Coefficients of the O2 Schumann—Runge Continuum from 1270 Å ↔ 1745 Å using a New Continuum Source," J. Opt. Soc. Am. 56, 765-766 (1966)