Eight common dialkylimidazolium-based ionic liquids have been successfully evaporated in ultra-high vacuum and their vapours analysed by line of sight mass spectrometry using electron ionisation. The ionic liquids investigated were 1-alkyl-3-methylimidazolium bis[(trifluoromethane)sulfonyl]imide, [C(n)C(1)Im][Tf(2)N] (where n = 2, 4, 6, 8), 1-alkyl-3-methylimidazolium tetrafluoroborate, [C(n)C(...

The solar wind modulates the flux of galactic cosmic rays impinging on Earth inversely with solar activity. Cosmic ray ionisation is the major source of air’s electrical conductivity over the oceans and well above the continents. Differential solar modulation of the cosmic ray energy spectrum modifies the cosmic ray ionisation at different latitudes, varying the total atmospheric columnar condu...

Context. Determining the properties of solar-like oscillating stars can be subject to many biases. A particularly important example is helium-mass degeneracy, where uncertainties regarding internal physics cause a poor determination both mass and surface helium content. Accordingly, an independent estimate needed overcome this degeneracy. promising way obtain such exploit so-called ionisation g...

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...

Static secondary ion mass spectrometry (S-SIMS) is one of the potentially most powerful and versatile tools for the analysis of surface components at the monolayer level. Current improvements in detection limit (LOD) and molecular specificity rely on the optimisation of the desorption-ionisation (DI) process. As an alternative to monoatomic projectiles, polyatomic primary ion (P.I.) bombardment...

We present a new implicit numerical algorithm for the calculation of the time dependent non-Local Thermodynamic Equilibrium of a gas in an external radiation field that is accurate, fast and unconditionally stable for all spatial and temporal increments. The method is presented as a backward difference scheme in 1-D but can be readily generalised to 3-D. We apply the method for calculating the ...

We present a spectral analysis of the narrow-line Seyfert 1 galaxy I Zwicky 1, focusing on the characteristics of the ionised absorbers as observed with XMM-Newton in 2005. The soft X-ray spectrum shows absorption by two components of ionised gas with a similar column density (N H ∼ 10 21 cm −2) and ionisation parameters log ξ ∼ 0 and 2.5. Comparing this observation with a 2002 XMM-Newton data ...