Showing papers by "Tsing-Hua Her published in 1995"
01 Sep 1995
TL;DR: In this paper, the authors reported the fluence dependent yields obtained over a range of laser wavelengths from 267 to 800 nm, and pulse durations from 80 fs to 3.6 ps.
Abstract: Desorption of OZ and formation of CO2 were induced with subpicosecond laser pulses on a Pt(111) surface dosed with coadsorbed OZ and CO. We report the fluence dependent yields obtained over a range of laser wavelengths from 267 to 800 nm, and pulse durations from 80 fs to 3.6 ps. The nonlinear dependence of the yield on fluence is different at different wavelengths. Two-pulse correlation measurements show two different time-scales relevant to the desorption. The results show that nonthermalized electrons play a role in the surface chemistry, and that an equilibrated pre-heating of the surface modes leads to enhanced desorption.
66 citations
25 Sep 1995
TL;DR: In this article, the nonlinear fluence dependent reaction yields were measured for 267, 400, and 800 nm wavelengths, and for pulse durations from 80 fs to 3.6 ps.
Abstract: Laser induced formation of CO2 and desorption of O2 are initiated with femtosecond and picosecond laser excitation of a Pt(111) surface prepared with coadsorbed CO and O2 at 90 K. The nonlinear fluence dependent reaction yields were measured for 267, 400, and 800 nm wavelengths, and for pulse durations from 80 fs to 3.6 ps. Two-pulse correlation experiments measuring total O2 desorption yield versus time delay between 80 fs pulses show a 0.9 ps HWHM central peak and a slower 0.1 ns time-scale. At 267 nm the relative yields of O2 and CO2 are found to depend on fluence. Comparison of results at different wavelengths and pulsewidths shows that nonthermalized surface electrons play a role in the laser-induced surface chemistry.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
3 citations