Fragmentation of molecules by fast ion impact
نویسندگان
چکیده
Abstract. Single ionization of simple molecules, e.g. H2, CO2, by fast charged particle impact has been studied using a reaction microscope. By measuring the momenta of the emitted electron and the recoil ionic fragment in coincidence, channel-selective low-energy electron spectra have been recorded. The experimental cross sections will be presented, compared with the predictions of state-of-the-art CDW-EIS calculations and discussed in terms of molecular effects such as (i) autoionization and predissociation channels, (ii) interference patterns resulting from the two-center geometry of the diatomic molecule, in analogy to Young’s double-slit experiment and (iii) dependence of the electron emission on the orientation of the molecular axis.
منابع مشابه
A Beginner's Guide to Mass Spectrometry of Fatty
At its simplest, mass spectrometry (MS) is a technique in which organic molecules are bombarded by electrons or other ionic species causing them to ionize and fragment. We use the fragmentation patterns as a means of identification. If you pick up a journal dealing with mass spectrometry, there will be a host of technical terms dealing with methods of ionization especially, such as "electrospra...
متن کاملIon-water collisions at intermediate energies
Synopsis We employ the independent event electron model in the framework of the classical trajectory Monte Carlo method to compute ionization and capture cross sections for oneand twoelectron processes in collisions of H, He and C with water molecules at intermediate impact energies. Subsequente fragmentation processes are also considered, as well as the differential cross sections for electron...
متن کاملFirst Principles Based Reactive Atomistic Simulations to Understand the Effects of Molecular Hypervelocity Impact on Cassini’s Ion and Neutral Mass
Introduction: NASA's Cassini Cassini's Ion and Neutral Mass Spectrometer (INMS) has returned a wealth of data on the composition of Titan's upper atmosphere and the plumes of Enceladus. However the encounter velocity (up to 17.73 km/sec) of the spacecraft with the plume or atmosphere has profound effects on the fragmentation of the observed molecules. Measured compositional changes of H 2 O, H ...
متن کاملDETECTION OF CROSS-LINmD PERIDES BY FAST ATOM B01WBARDMENT MASS SPECTROMETRY
The possibility of chemical modification of peptides and proteins under the condition of proteolytic digestions and FABMS analysis was investigated. The results ;indicate that among the amino acid constituents of peptides and proteins: serinefcysteine, and cystine are the most sensitive residues which undergo chemical modificadons under the exprimenta1 conditions. The chemical modification ...
متن کاملRecoil-Ion and Electron Momentum Spectroscopy: Reaction-Microscopes
Recoil-ion and electron momentum spectroscopy is a rapidly developing technique that allows one to measure the vector momenta of several ions and electrons resulting from atomic or molecular fragmentation. In a unique combination, large solid angles close to π 4 and superior momentum resolutions around a few percent of an atomic unit ( . .u a ) are typically reached in state-of-the art machines...
متن کامل