Neutral magnesium atom emission from nanostructured MgO thin films is induced using two-color nanosecond laser excitation. We find that combined visible/UV excitation, for single-color pulse energies below the desorption threshold, induces neutral Mg-atom emission with hyperthermal kinetic energies in the range of 0.1- 0.2 eV. The observed metal atom emission is consistent with a mechanism involving rapid electron transfer to 3-coordinated Mg surface sites. The two-color Mg-atom signal is significant only for parallel laser polarizations and temporally overlapped laser pulses indicating that intermediate excited states are short-lived compared to the 5 nanosecond laser pulse duration.
Revised: March 16, 2010 |
Published: September 30, 2009
Citation
Beck K.M., A.G. Joly, and W.P. Hess. 2009.Two-color Laser Desorption of Nanostructured MgO Thin Films.Applied Surface Science 255, no. 24:9562-9565.PNNL-SA-62094.doi:10.1016/j.apsusc.2009.04.089