Temperature dependence of absorption cross-section of H₂O, HOD, and D₂O in the spectral region 140-193nm

Measurements of absolute photoabsorption cross-sections of H₂O, D₂O and HOD in the spectral range 140-195nm were performed at 295, 275, and 250K using a double-beam absorption cell with a synchrotron radiation source. The absorption cross-sections in the spectral range 150-174 nm are nearly invariant upon isotopic substitution, but become smaller for heavier isotopomers in the region λ >174 nm. For each isotopomer, absorption cross-sections are nearly temperature independent in the spectral range 140-173 nm, but exhibit a small negative temperature dependence for wavelengths greater than 173 nm.