Dissociation Dynamics of CIONO_2 and Relative Cl and ClO Product Yields following Photoexcitation at 308 nm

Chlorine nitrate photolysis at 308 nm has been investigated with a molecular beam technique. Two primary decomposition pathways, leading to Cl + NO_3 and ClO + NO_2, were observed. The branching ratio between these two respective channels was determined to be 0.67 ± 0.06 : 0.33 ± 0.06. This ratio is an upper limit because some of the ClO photoproducts may have undergone secondary photodissociation. The angular distributions of the photoproducts with respect to the direction of polarization of the exciting light were anisotropic. The anisotropy parameters were β= 0.5 ± 0.2 for the Cl + NO_3 channel and β= 1.1 ± 0.2 for the ClO + NO_2 channel, indicating that dissociation of ClONO_2 by either pathway occurs within a rotational period. Weak signal at mass-to-charge ratios of 35 and 51, arising from products with laboratory velocities close to the beam velocity, was observed. While this signal could result from statistical dissociation channels with a total relative yield of 0.07 or less, it is more likely attributable to products from ClO secondary photodissociation or from dissociation of clusters

10th meeting of the International Conference on Protection of Materials and Structures from Space Environment

The goals of the 10th International Space Conference on “Protection of Materials and Structures from Space Environment” ICPMSE-10J, since its inception in 1992, have been to facilitate exchanges between members of the various engineering and science disciplines involved in the development of space materials, including aspects of LEO, GEO and Deep Space environments, ground-based qualification, and in-flight experiments and lessons learned from operational vehicles that are closely interrelated to disciplines of the atmospheric sciences, solar-terrestrial interactions and space life sciences. The knowledge of environmental conditions on and around the Moon, Mars, Venus and the low Earth orbit as well as other possible candidates for landing such as asteroids have become an important issue, and protecting both hardware and human life from the effects of space environments has taken on a new meaning in light of the increased interest in space travel and colonization of other planets.  And while many material experiments have been carried out on the ground and in open space in the last 50 years (LDEF, MEEP, SARE, MISSE, AOP, DSPSE, ESEM, EURECA, HST, MDIM, MIS, MPID, MPAC and SEED), many questions regarding the environmental impact of space on materials remain either poorly understood or unanswered. The coming generations of scientists will have to continue this work and tackle new challenges, continuing to build the level of confidence humans will need to continue the colonization of space. It is hoped that the proceedings of the ICPMSE-10J presented in this book will constitute a small contribution to doing so

Oxidation of Si(001) with a hyperthermal O-atom beam at room temperature: Suboxide distribution and residual order structure

Masahito Tagawa, Chie Sogo, Akitaka Yoshigoe and Yuden Teraoka, "Oxidation of Si(001) with a hyperthermal O-atom beam at room temperature: Suboxide distribution and residual order structure", Appl. Phys. Lett. 88, 133512 (2006) https://doi.org/10.1063/1.2190467