Oxygen Atoms Make a Fast Escape
The right laser wavelength accelerates and removes oxygen from thin films
Scientists from Pacific Northwest National Laboratory, University College of London, and Tohoku University have discovered a new way to accelerate and remove oxygen atoms from thin films of calcium oxide. The team included EMSL visiting scientist Alex Shluger of the Department of Physics and Astronomy faculty at University College London, who was one of the inaugural participants in EMSL’s Wiley Visiting Scientist Program in 2009. The team found a way to remove oxygen from the surface of nanostructured films of calcium oxide at many times the speed of sound by choosing the appropriate laser wavelength. They used a technique developed at PNNL called reactive ballistic deposition to grow a nanostructured film of calcium oxide, and using laser pulses to excite the film, they applied EMSL’s specialized time-of-flight techniques to measure the kinetic energy and yield of desorbed oxygen atoms. By selecting the laser wavelength, they were able to produce highly energetic atoms from the film surface. The scientists demonstrated that tuning the laser wavelength makes it possible to manipulate particular molecular structures on a material surface. This research has implications for research and development in photochemistry, catalysis, and microelectronics. It was featured on the cover of The Journal of Physical Chemistry C for January 27, 2011.
Reference: Sushko PV, AL Shluger, AG Joly, KM Beck, and WP Hess. 2011. "Exciton-Driven Highly Hyperthermal O-Atom Desorption from Nanostructured CaO." Journal of Physical Chemistry C, 115 (3), 692-699. DOI: 10.1021/jp1078423.
Acknowledgement: This research was funded by the U.S. Department of Energy Office of Basic Energy Sciences.
Released: March 23, 2011