Threshold Energies for Single-Carbon Knockout from
Polycyclic Aromatic Hydrocarbons
M. H. Stockett
M. Gatchell
T. Chen
N. de Ruette
L. Giacomozzi
M. Wolf
H. T. Schmidt
H. Zettergren
H. Cederquist
10.1021/acs.jpclett.5b02080.s001
https://acs.figshare.com/articles/journal_contribution/Threshold_Energies_for_Single_Carbon_Knockout_from_Polycyclic_Aromatic_Hydrocarbons/2006028
We
have measured absolute cross sections for ultrafast (femtosecond)
single-carbon knockout from polycyclic aromatic hydrocarbon (PAH)
cations as functions of He–PAH
center-of-mass collision energy in the 10–200 eV range. Classical
molecular dynamics (MD) simulations cover this range and extend up
to 10<sup>5</sup> eV. The shapes of the knockout cross sections are
well-described by a simple analytical expression yielding experimental
and MD threshold energies of <i>E</i><sub>th</sub><sup>Exp</sup> = 32.5 ± 0.4 eV and <i>E</i><sub>th</sub><sup>MD</sup> = 41.0 ± 0.3 eV, respectively. These are the first measurements
of knockout threshold energies for molecules isolated in vacuo. We
further deduce semiempirical (SE) and MD displacement energies, i.e.,
the energy transfers to the PAH molecules at the threshold energies
for knockout, of <i>T</i><sub>disp</sub><sup>SE</sup> = 23.3 ± 0.3 eV and <i>T</i><sub>disp</sub><sup>MD</sup> = 27.0
± 0.3 eV. The semiempirical results compare favorably with measured
displacement energies for graphene (<i>T</i><sub>disp</sub> = 23.6 eV).
2015-12-17 10:44:08
PAH molecules
energy transfers
23.6 eV
knockout threshold energies
Polycyclic Aromatic HydrocarbonsWe
0.3
MD displacement energies
displacement energies
threshold energies
MD threshold energies
threshold Energies
105 eV
SE