High-temperature ultrahigh-resolution absorption cross-section measurements of O2 in the EUV region

Symmetry-Resolved Absorption Spectra of Vibrationally ExcitedCO2Molecules

“…CO 2 constitutes about 95% of Venus's atmosphere, the average surface of which is 460 C. At such temperatures, the molecules are partially vibrationally excited and these molecular vibrations must be taken into account for proper atmospheric modeling [1]. However, there are only a few studies of vibrationally excited hot molecules in the region of the extreme vacuum ultraviolet absorption spectroscopy [2] and in the area of low-energy electron collisions [3]. To our knowledge, no xray absorption study has been reported so far on any hot molecules.…”

Measurements of rovibronic line oscillator strengths of N2 in the 83.4 nm region: A high‐resolution high‐temperature study

“…In the present work, our data shown in Figures 2a, 2b and 2c reflect the effects of temperature on the band contours and, especially, in the perturbed spectral region in which two of the OII triplet mulltiplet lines are located. As a result, the present N 2 data and our high‐temperature high‐resolution cross‐section data of O 2 at 83.4 nm [ Wu et al , 2005, 2001] will allow us to better model the OII 83.4 nm EUV airglow emission of the Earth. The high‐resolution high‐temperature cross‐section measurements of N 2 at other prominent EUV airglow lines, e.g., the NII 91.7 nm, are currently in progress in our laboratory and will be the subject of a future publication.…”

“…Briefly, it consists of an intense light source, a high‐temperature windowless absorption cell, an ultrahigh‐resolution spectrometer, and a data acquisition system. The windowless high‐temperature (300 to 900 K) absorption cells with a path length of 16.24 cm [ Wu et al , 1998] and 11.7 cm [ Wu et al , 2005, 2000] and with two 1.0 mm diameter apertures were used in the absorption cross‐section measurements. This windowless, high‐temperature cell is a unique facility and is the only one in the world that is currently in operation associated with high‐resolution cross‐section studies.…”

“…The reciprocal linear dispersion is 0.02 nm/mm in the sixth order, which gives a resolving power of 3 × 10 5 in the 83.4 nm spectral region. The resolution of the 6‐VOPE facility is 3 × 10 −4 nm in the photographic mode and 6 × 10 −4 nm in the photoelectric mode using a stepping speed of 1.4 × 10 −4 nm/step [ Wu et al , 2005, 2000] and 7 × 10 −5 nm/step [ Wu et al , 1998]. The photoelectric mode was employed in the present work.…”

“…Therefore in the present work we report measurements of the integrated oscillator strength ( f ‐value) for each rovibronic line. We have previously carried out similar measurements in the O 2 molecule but with a lower resolution [ Wu et al , 2005, 2001, 2000].…”