Formation of HCN in collisions of N and N with a self-assembled propanethiol surface on gold.

Collisions of N and N with C3 hydrocarbons, represented by a self assembled monolayer of propanethiol on a polcrystalline gold surface, were investigated by experiments over the incident energy range between 5 eV and 100 eV. For N, formation of HCN is observed at incident energies of projectile ions as low as 20 eV. In the case of N projectile ions, the yield of HCN increased above zero only at incident energies of about 50 eV.

A high sensitivity, high resolution tandem mass spectrometer to research low-energy, reactive ion-surface interactions.

The device described is the combination of two mass spectrometers, with a surface sample placed between them. Its aim is to allow for detailed research on low-energy ion-surface interactions, involving and triggering surface chemistry. This task is fulfilled by a carefully chosen geometry: Projectile ions from an electron impact source are mass-per-charge selected using a quadrupole.

An intense source for cold cluster ions of a specific composition.

The demand for nanoscale materials of ultra-high purity and narrow size distribution is addressed. Clusters of Au, C, HO, and serine are produced inside helium nanodroplets using a combination of ionization, mass filtering, collisions with atomic or molecular vapor, and electrostatic extraction, in a specific and novel sequence. The helium droplets are produced in an expansion of cold helium gas through a nozzle into vacuum.

Ionization of Ammonia Nanoices with Adsorbed Methanol Molecules.

Large ammonia clusters represent a model system of ices that are omnipresent throughout the space. The interaction of ammonia ices with other hydrogen-boding molecules such as methanol or water and their behavior upon an ionization are thus relevant in the astrochemical context. In this study, ammonia clusters (NH) with the mean size N̅ ≈ 230 were prepared in molecular beams and passed through a pickup cell in which methanol molecules were adsorbed.