Electron scattering from molecules and molecular aggregates of biological relevance

In this Topical Review we survey the current state of the art in the study of low energy electron collisions with biologically relevant molecules and molecular clusters. We briefly describe the methods and techniques used in the investigation of these processes and summarise the results obtained so far for DNA constituents and their model compounds, amino acids, peptides and other biomolecules. The applications of the data obtained is briefly described as well as future required developments

Negative ion formation mechanism and velocity distribution in laser desorption/ionization of C

In UV laser desorption/ionization (LDI) of C60, both molecular cations and anions are formed. While the C60+ formation has been discussed in a number of studies and is fairly well understood, the C60- formation has received less attention. Here, we present measurements of C60- and C60+ formation and its fluence dependence in UV-LDI of C60 from both metallic and non-metallic substrates. The data show clearly that the C60- formation is coupled to the C60+ formation, indicating that C60- is predominantly formed through electron transfer early in the expanding laser desorption plume. The velocity distribution of desorbed C60- ions was also determined and was found to be best described by two Maxwell-Boltzmann distributions with superimposed stream velocities

Metastable decay of DNA components and their compositions – a perspective on the role of reactive electron scattering in radiation damage

Here we review recent studies on the metastable fragmentation of individual DNA and RNA building blocks and their compositions using matrix assisted laser desorption/ionization mass spectrometry (MALDI). To compare the fragmentation channels of small DNA components with larger compositions we have studied the metastable fragmentation of the deprotonated nucleobases, ribose, ribose-monophoshates, the nucleosides, the nucleoside 5′-monophosphates and selected oligonucleotides. Both previously published and unpublished data are reported. To gain a comprehensive picture of the fragmentation of individual components, metastable fragmentation of native components are in many cases compared to chemically modified components and isotopic labelling is used to unambiguously identify fragments. Furthermore, to shed light on the underlying fragmentation mechanisms we complement the experimental studies with classical dynamics simulations of the fragmentation of selected compounds. For the DNA and RNA components where dissociative electron attachment studies have been conducted we compare these to the metastable fragmentation channels observed here