When a molecule loses two electrons, Coulomb repulsion makes the resulting doubly charged system likely to fragment into two singly charged ions. These monocations can be detected in a correlated fashion using multiplex time-of-flight spectroscopy. The island shapes in the ion-ion coincidence maps derived from such two-body dissociations contain detailed information on the physical processes underlying the fragmentation.
View Article and Find Full Text PDFDouble ionization spectra of isothiocyanic acid (HNCS) have been measured using multi-electron and multi-ion coincidence techniques combined with high-level theoretical calculations. The adiabatic double ionization energy of HNCS is found at 27.1 ± 0.
View Article and Find Full Text PDFThe dissociation of OCS ions formed by photoionization of the neutral molecule at 40.81 eV is examined using threefold and fourfold electron-ion coincidence spectroscopy combined with high level quantum chemical calculations on isomeric structures and their potential energy surfaces. The dominant dissociation channel of [OCS] is charge separation forming CO + S ion pairs, found here to be formed with low intensity at a lower-energy onset and with a correspondingly smaller kinetic energy release than in the more intense higher energy channel previously reported.
View Article and Find Full Text PDFConventional electron spectroscopy is an established one-electron-at-the-time method for revealing the electronic structure and dynamics of either valence or inner shell ionized systems. By combining an electron-electron coincidence technique with the use of soft X-radiation we have measured a double ionisation spectrum of the allene molecule in which one electron is removed from a C1s core orbital and one from a valence orbital, well beyond Siegbahns Electron-Spectroscopy-for-Chemical-Analysis method. This core-valence double ionisation spectrum shows the effect of symmetry breaking in an extraordinary way, when the core electron is ejected from one of the two outer carbon atoms.
View Article and Find Full Text PDFMolecular oxygen, O, is vital to life on Earth and possibly also on exoplanets. Although the biogenic processes leading to its accumulation in Earth's atmosphere are well understood, its abiotic origin is still not fully established. Here, we report combined experimental and theoretical evidence for electronic state-selective production of O from SO, a chemical constituent of many planetary atmospheres and one that played an important part on Earth in the Great Oxidation Event.
View Article and Find Full Text PDFUsing time-of-flight multiple electron and ion coincidence techniques in combination with a helium gas discharge lamp and synchrotron radiation, the double ionisation spectrum of disulfur (S[Formula: see text]) and the subsequent fragmentation dynamics of its dication are investigated. The S[Formula: see text] sample was produced by heating mercury sulfide (HgS), whose vapour at a suitably chosen temperature consists primarily of two constituents: S[Formula: see text] and atomic Hg. A multi-particle-coincidence technique is thus particularly useful for retrieving spectra of S[Formula: see text] from ionisation of the mixed vapour.
View Article and Find Full Text PDFBackground: Patients who call for emergency medical services (EMS) due to abdominal pain suffer from a broad spectrum of diseases, some of which are time sensitive. As a result of the introduction of the concept of 'optimal level of care', some patients with abdominal pain are triaged to other levels of care than in an emergency department (ED). We hypothesised that it could be challenging in a patient safety perspective.
View Article and Find Full Text PDFDouble 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 formation by double ionization. The lowest vertical double ionization energy is found to be 27.
View Article and Find Full Text PDFThe dissociations of nascent Fe(CO) ions created by 40.81 eV photoionization of iron pentacarbonyl have been examined using threefold and fourfold electron-ion coincidence measurements. The energies and forms of the ions have been explored by high-level calculations, revealing several new structures.
View Article and Find Full Text PDFDysregulation of the central noradrenergic system is a core feature of post-traumatic stress disorder (PTSD). Here, we examined molecular changes in locus coeruleus (LC) triggered by single-prolonged stress (SPS) PTSD model at a time when behavioral symptoms are manifested, and the effect of early intervention with intranasal neuropeptide Y (NPY). Immediately following SPS stressors, male SD rats were administered intranasal NPY (SPS/NPY) or vehicle (SPS/V).
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