Electronic effects in the dissociative ionisation of pyrene clusters

Abstract

We present a combined experimental and theoretical study on the dissociative ionisation of clusters of pyrene that shows non-statistical behaviour and suggests that the role of excited states must be considered in the interpretation of the results.

Addressing electronic and dynamical evolution of molecules and molecular clusters: DFTB simulations of energy relaxation in polycyclic aromatic hydrocarbons

“…Surprisingly, two of these experiments derived different threshold photon energies for the monomer apparition, namely 0.6 221 or 1.7 eV. 222 In addition, these two values also differ from those of the argon collision induced dissociation experiment 214 which agreed with the theoretical ground state binding energies of 1.07 eV 215 as already discussed in Section 3.3. This apparent contradiction is related to the initial conditions of the system and the fact that the energy levels of the electronically excited states and their topologies may play a crucial role.…”

“…In the second photodissociation experiment 222 carried out at the SOLEIL Synchrotron facility, neutral pyrene dimers prepared at low temperatures absorb a photon whose energy can be tuned. It is then possible to detect whether the photoabsorption leads to simple ionization (detection of Py 2 + , black curve in Fig.…”

Photoionization Dynamics and Proton Transfer within the Adenine-Thymine Nucleobase Pair

“…To analyze small shifts in kinetic energy distributions with a change in photon energy, we used the ratio of high-KE ions above a chosen threshold determined from normalized ion kinetic energy distributions . These data sets were fitted with a bilinear model to determine the photon energies corresponding to an onset of an increase in ion kinetic energy, corresponding to a dissociative ionization threshold.…”

“…To analyze small shifts in kinetic energy distributions with a change in photon energy, we used the ratio of high-KE ions above a chosen threshold determined from normalized ion kinetic energy distributions. 47 These data sets were fitted with a bilinear model to determine the photon energies corresponding to an onset of an increase in ion kinetic energy, corresponding to a dissociative ionization threshold. To verify the independence of the determined onsets from the chosen energy threshold values in the determination of the fractional high-KE ion signals, the analysis was repeated for a wide range of threshold values, and the slightly varying resulting thresholds were averaged (see the Supporting Information).…”

Coincidence mass spectrometry study of double ionization of pyrene by 70 eV electron impact

“…[44][45][46][47][48] Yamakita et al 49 have measured penning ionization electron spectra of pyrene, chrysene, and coronene in collision with metastable helium atoms. Several groups have researched the fragmentation of pyrene clusters and solvated pyrene molecules in collisions with photons [50][51][52] and with ions. 35,53,54 The photochemistry of pyrene in water ice has also been studied.…”