The establishment of EVISA is funded by the EU through
the Fifth Framework Programme (G7RT- CT- 2002- 05112).
Supporters of EVISA includes:
The appearance energy (or appearance potential) is the lowest energy which must be imparted to the parent molecule to cause it to produce a particular specified ion. This energy, usually stated in electron volts, may be imparted by electron impact, by photon impact, or in other ways. (Note: It is recommended that the term 'appearance energy' should replace the term 'appearance potential' and that the energy should be stated in SI units.)