N2O 在 Ag(111) 上的紫外光光解和光脱附。

UV photo-dissociation and photodesorption of N2O on Ag(111).

机构信息

Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.

出版信息

J Phys Condens Matter. 2010 Mar 3;22(8):084012. doi: 10.1088/0953-8984/22/8/084012.

Abstract

Nanosecond laser induced photoreactions of N2O adsorbed on Ag(111) have been studied by temperature programmed desorption (TPD) and mass-selected, angle-dependent time-of-flight (MS-TOF) measurements of neutral desorbing particles. N2O molecules in the first monolayer are thermally inert but photo-dissociate into N2 + O, or photodesorb molecularly or dissociatively, at photon energies above 3.5 eV. We have found that TOF spectra of photodesorbed N2 as well as of N2O measured at hν = 4.7 eV consist of two velocity components. The desorption flux of the fastest component of N2O peaks ∼ 25° off the surface normal, whereas the others are directed in the surface normal. Origins and photo-excitation as well as photodesorption mechanisms of the N2O and N2 signals are discussed.

摘要

利用程序升温脱附（TPD）和中性脱附粒子的质量选择、角度相关飞行时间（MS-TOF）测量，研究了 N2O 在 Ag（111）上吸附的纳秒激光诱导光反应。第一层中的 N2O 分子在热上是惰性的，但在光子能量高于 3.5 eV 时，光解为 N2 + O，或分子或离解光解。我们发现，在 hν = 4.7 eV 时测量的光解 N2 和 N2O 的飞行时间谱由两个速度分量组成。N2O 的最快分量的脱附通量在表面法线的约 25°处达到峰值，而其他分量则指向表面法线。讨论了 N2O 和 N2 信号的光激发和光解机制的起源。