低温表面吸附过氧化二叔丁基的激光脱附和解离

Laser -induced Desorption and Photofragmentation of Di - tert-butyl Peroxide Adsorbed on Surfaces

本文研究了过氧化二叔丁基(DTBP)低温吸附于银表面(110K)和石英(130K)表面经紫外(266nm)激光辐照后引起的脱附和光解离过程.用时间分辨质谱技术测定和分析了脱附和光解离产物,发现在银表面上DTBP同时发生光脱附和热脱附;在激光能量密度较高时还伴有该分子中O-O键断裂的光解离.当紫外激光辐照吸附在石英表面上的DTBP分子时,除了发生上述光脱附和光解离过程之外,还伴有由DTBP中C-O键断裂而产生(CH_3)_3C·自由基的光解反应.

The laser- induced desorption and fragmentation of di - tert - butyl peroxide (DTBP) adsorbed on the Ag (110K) and quartz (130K) surfaces are investigated using time -resolved mass spectrometric technique. The time - of - flight (TOF) spectra of desorbed and dissociated products are measured at different laser fluences. The analysis of TOF spectra show that the UV laser - induced desorption of multilayer of DTBP on Ag surface proceeds via both photochemical desorption and thermal desorption at lower fluence,and the primary photodissociation occurs with rupture of the weak O-O bond at high laser fluence. For the DTBP/quartz system, the laser-induced photodesorption and fragmentation with two different channels take place i. e.