We present an ionisation model for Polycyclic Aromatic Hydrocarbon (PAH) molecules fromwhich we determine the various size dependant ionisation states expected in different space environments.Maps of ionisation regimes are derived. They allow the estimate of the ionisation fraction of PAH for any given set of parameters (electron density, flux factor and temperature) assuming a typical PAH size...

Vertical soundings of the atmospheric ion production rate have been obtained from Geiger counters integrated with conventional meteorological radiosondes. In launches made from Reading (UK) during 2013–2014, the Regener–Pfotzer ionisation maximum was at an altitude equivalent to a pressure of (63.172.4) hPa, or, expressed in terms of the local air density, (0.10170.005) kg m . The measured ioni...

We analyse the evolution of the fractional ionisation in a steady-state protoplanetary disc over 10 yr. We consider a disc model with a vertical temperature gradient and with gas-grain chemistry including surface reactions. The ionisation due to stellar X-rays, stellar and interstellar UV radiation, cosmic rays and radionuclide decay is taken into account. Using our reduction schemes as a tool ...

This paper considers the chemistry in a protoplanetary accretion disk during the viscous stage. The model calculation extends our previous work by including in the chemical reaction network the ionisation processes due to cosmic rays and especially the ionisation due to the extinct radio-nuclides 26Al and 60Fe which are known to have been present at the time of formation of our own solar system...

We use velocity map imaging of photoelectrons in coincidence with molecular cations to determine which ionic states are populated via strong field ionisation, and whether the ionisation to excited ionic states proceeds indirectly via the ground ionic state or directly from the neutral. We carry out measurements on a series of molecules that have different energy gaps between the ground ionic st...

A simple theory of the Rydberg atoms ionisation by electromagnetic pulses and microwave field is presented. The analysis is based on the scale transformation which reduces the number of parameters and reveals the functional dependencies of the processes. It is shown that the observed ionisation of Rydberg atoms by subpicosecond electromagnetic pulses scale classically. The threshold electric fi...

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...