Absorption cross section of molecular oxygen in the transition E3Σu-v= 0 – X3Σg-v= 0 at 38 K

Abstract

Aims. This investigation was undertaken to determine the absorption cross sections of oxygen in the VUV region at temperatures <50 K. Methods. The absorption spectra of gaseous samples cooled with a slit jet and near 300 K were measured with the same absorption system coupled to the VUV beam line of a synchrotron. Results. The maximum absorption cross section for the transition from X 3 Σ − v = 0 to state E 3 Σ − v = 0f or 16 O2 at 38 K was determined to be 98.7 Mb (or 9.87 × 10 −18 cm 2 ). The value of this maximum absorption cross section at 38 K is 1.7 times the value at 303.7 K.