Instrumatational development of laser spectroscopic analyzer for mass-selected RF ion trapped species

点击翻译按钮获取中文摘要

1.Stable forms of cations of phenol complexed with hydrogen-accepting molecules such as NH_3, H_2O or p-dioxane were investigated with trapped ion photodissociation spectroscopy. Electronic spectra in the range 366-465 nm reveal that the ground-state ion of the phenol-NH_3 complex consists of a phenoxy radical and an ammonium ion, whereas other ions are complexes of phenol ions with unprotonated acceptors. Dissociation processes involving the proton transfer in the ground and the excited states of the ions are discussed.2.Electronic spectra of hydrogen-bonded complex cations of phenol with N(CH_3)_3. NH_3 and H_2O were investigated by photodissociation spectroscopy combined with a new method for the generation of jet-cooled molecular complex ions. The method involves the ionization of phenol followed by a jet expansion for the efficient formation of the complex ions as well as for the cooling. Well-resolved vibronic bands, including the bands due to intermolecular stretching vibrations, were obtained for the complex ions of phenol with N(CH_3)_3 and NH_3. Differences between the ionic and neutral forms of these complexes were discussed on the basis of the results.3.A new technique is proposed for spatially confining mass-selected ions and extracting them to a solid surface at low kinetic energy. This technique combines rf ion trapping with multiphoton ionization by a KrF excimer laser. SF_5^+ ions photodissociated from SF_6 were separated from other ionic species and stored in the cylindrical ion trap cell for at least 100ms. The stored ions were extracted onto the surface with low kinetic energies around 10eV.This technique should be useful for studying surface reactions with mass-selected, state-specified, and very-low-kinetic-energy ions and for developing etching processes that can be used to control the surface structure of semiconductors on an atomic scale.