Probing the dynamics of the photo-induced decarboxylation of neutral and ionic pyruvic acid

Abstract

The dynamics of the electronically excited pyruvic acid (PA) and of its unimolecular decomposition upon single photon ionization are investigated by means of a table top fs laser and VUV...

Vacuum Ultraviolet Single Photon Ionization and Decomposition of 2-Aminopropionitrile in Astrophysical Objects

“…All four ions have experimental AEs around 10.5 eV (see Figure 5 for exact values) indicating that these channels are all open when populating higher vibrational levels of the cationic ground state. Such a situation was already observed, for instance, during the dissociative single photon ionization of pyruvic acid (Jarraya et al 2022) via CC bond breaking, where both direct and indirect photoionization processes coupled with fragmentation are in action. Full elucidation of such phenomena requires in-depth treatment of the electronic states of the 2-APN + cation, which is out of the scope of the present work.…”

“…To this end, the "anharmonic zero-point energy" calculated in the Gaussian16 software was taken into account. This level of theory was chosen on the basis of comparisons with CCSD reference calculations because of its accuracy in reproducing experimental data at a reasonable computational cost (Pan et al 2013;Majdi et al 2015;Derbali et al 2020;Jarraya et al 2022). For all the calculations, 2-APN was considered in its most stable conformation.…”

Accounting for molecular flexibility in photoionization: case of tert-butyl hydroperoxide

“…The latter may be in action at the rotational and/or vibrational and/or electronic levels, where an enhancement of respective bands is observed. 60,61 However, it should be noted that in Fig. 8 the simulated spectra had to be shifted by 156 meV from the coupled cluster AIE value to fit the experimental spectrum, meaning that the FC simulations rather support an AIE of ∼9.4 eV.…”

“…For rigid or semi-rigid molecules, the approach is straightforward and can be used in fully automated procedures as we recently showed for methyl adenine and pyruvic acid. 53,61 For such flexible species, the choice of a suitable coordinate system remains a difficult challenge, even done manually. An interesting aspect highlighted in this work is that instruments/gauges exist to assess quantitatively the validity of the representation adopted for the description of the vibrational motions.…”