Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Single photon double and triple ionisation of allene   Double and triple ionization of allene are investigated using
electron-electron, ion-ion, electron-electron-ion and electron-electron-ion-ion
(ee, ii, eei, eeii) coincidence spectroscopies at selected photon energies. The
results provide supporting evidence for a previously proposed roaming mechanism
in H$_3^+$ formation by double ionisation. The lowest vertical double
ionization energy is found to be 28.5 eV, while adiabatic double ionisation is
not accessed by vertical ionisation at the neutral geometry. The triple
ionization energy is found to be close to 50 eV in agreement with theoretical
predictions. The doubly charged parent ion is stable up to about 2 eV above
threshold, after which dissociations by charge separation and by double charge
retention occur with comparable intensities. Fragmentation to H$^+$ +
C$_3$H$_3^+$ starts immediately above threshold as a slow (metastable) decay
with 130+/-10 ns mean lifetime.

2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess