The chemical ionisation mass spectra of seven naturally occurring depsipeptides and some of their permethylated derivatives have been measured. The primary ionisation process involves an ester group and not an amide or other functionality. It probably occurs randomly when the molecule contains more than one ester link. Unlike electron impact mass spectra, those obtained under chemical ionisatio...

Electron impact cross sections sets are constructed for the nitrogen trifluoride, nitrogen difluoride and nitrogen monofluoride molecules. These cross sections are based on ab initio R-matrix calculations augmented by other procedures. Cross sections are presented for elastic collisions, momentum transfer, dissociative electron attachment, electron impact dissociation, ionisation and dissociati...

Abstract There are many measurements and calculations of total electron impact ionisation cross sections. However, applications, particularly in plasma physics, also require fragmentation patterns. Approximate methods deducing partial sections tested based on the use section computed within well-used binary encounter Bethe approximation. Partial for three series molecules including CH 4 , CF CC...

-In this work the five-fold differential doubleionisation cross section of helium by the impact of fast charged particles has been investigated. The case is considered in which little momentum is transferred to the target so that a Born-type approximation in the projectile-target potential can be employed. A scaling formula for the cross section has been derived which relates cross sections res...

The SPARC-EBIT (fig.1) is an Electron Beam Ion Trap (from DREEBIT, Dresden) that will be used for tests and offline measurements, firstly for HITRAP, and later for SPARC (Stored Particle Atomic physics Research Collaboration). In the EBIT the ions are produced by electron impact ionisation of gas atoms by an intense electron beam. The magnetic field of a permanent magnet arrangement focuses the...

Ionisation in collisions of alpha particles with hydrogen atoms has been investigated for impact energies lying between 2 and 900 keV amu-l. The multistate semiclassical impact parameter model with a two-centre expansion in travelling atomic orbitals was employed. The computed ionisation cross sections are, in particular in the low-energy region, in good agreement with the recent experimental d...