The absorption coefficient of SO2 under atmospheric conditions was measured at twenty DF laser lines. Weak absorption (α* ≲ 0.003 cm−1 atm−1) was found for a few wavelengths around 3.7 μm. Only the P4(6) line at 3.9843 μm (ν = 2509.86 cm−1) is strongly absorbed [α* = (0.44 ± 0.01) cm−1 atm−1]. The pressure dependence of the P4(6) cross section was measured. Self-broadening and foreign-gas broadening coefficients are between 1.5 and 5 MHz/Torr, and the distance from the P4(6) DF line to the center of the nearest SO2 line is (0.0043 ± 0.0004) cm−1.
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From Ref. 15, uncertainty ±0.003 cm−1. P4 lines from Ref. 12, uncertainty ±0.08 cm−1.
Zero entry means that the absorption is definitely smaller than the uncertainty of 0.001 cm−1
Table II
Specific Absorption of SO2 at DF Laser Wavelengths Around 3.7 μm; ptotal = pSO₂ = 320 mbar, Gas Temperature 20°C
Accuracy ±0.0005 cm−1.
Calculated from the absorption maxima in Ref. 11, accuracy ±1%.
Line A is not separated from line B, the value at line A relates to the total measured absorption; the value in brackets for line B is calculated.
Tables (3)
Table I
Specific Absorption of SO2 in N2 at DF Laser Wavelengths; ptotal = 1 bar, pSO₂ = 37.1 mbar[P4(6) line: 1.5-3 mbar]; Gas Temperature is 20°C
From Ref. 15, uncertainty ±0.003 cm−1. P4 lines from Ref. 12, uncertainty ±0.08 cm−1.
Zero entry means that the absorption is definitely smaller than the uncertainty of 0.001 cm−1
Table II
Specific Absorption of SO2 at DF Laser Wavelengths Around 3.7 μm; ptotal = pSO₂ = 320 mbar, Gas Temperature 20°C
Accuracy ±0.0005 cm−1.
Calculated from the absorption maxima in Ref. 11, accuracy ±1%.
Line A is not separated from line B, the value at line A relates to the total measured absorption; the value in brackets for line B is calculated.