Anionic and cationic photodissociation of the chloroform molecule excited in the vicinity of the Cl 1s edge

Photoionization and ionic dissociation of the C3 H3 NS molecule induced by soft X-ray near the C1s edge

Time of flight mass spectrometry, electron-ion coincidence, and ion yield spectroscopy were employed to investigate for the first time the thiazole (C₃ H₃ NS) molecule in the gas phase excited by synchrotron radiation in the soft X-ray domain. Total ion yield (TIY) and photoelectron-photoion coincidence (PEPICO) spectra were recorded as a function of the photon energy in the vicinity of the carbon K edge (C1s). The C1s resonant transitions as well as the core ionization thresholds have been determined from the profile of TIY spectrum, and the features were discussed. The corresponding partial ion yields were determined from the PEPICO spectra for the cation species produced upon the molecular photodissociation. Additional ab initio calculations have also been performed from where relevant structural and electronic configuration parameters were obtained for this molecule.

Breaking the disulfide chemical bond using high energy photons: the dimethyl disulfide and methyl propyl disulfide molecules

In order to study the stability of the disulfide chemical bond in molecules subjected to a flux of high energy photons, the ionic fragmentation of DMDS and MPDS has been studied following excitation around the S 1s edge (∼2470 eV).

Positive and negative ion formation in deep-core excited molecules: S 1s excitation in dimethyl sulfoxide

The photo-fragmentation of the dimethyl sulfoxide (DMSO) molecule was studied using synchrotron radiation and a magnetic mass spectrometer. The total cationic yield spectrum was recorded in the photon energy region around the sulfur K edge. The sulfur composition of the highest occupied molecular orbital's and lowest unoccupied molecular orbital's in the DMSO molecule has been obtained using both ab initio and density functional theory methods. Partial cation and anion-yield measurements were obtained in the same energy range. An intense resonance is observed at 2475.4 eV. Sulfur atomic ions present a richer structure around this resonant feature, as compared to other fragment ions. The yield curves are similar for most of the other ionic species, which we interpret as due to cascade Auger processes leading to multiply charged species which then undergo Coulomb explosion. The anions S(-), C(-), and O(-) are observed for the first time in deep-core-level excitation of DMSO.

Partial-ion-yield studies of SOCl2 following x-ray absorption around the S and Cl K edges

We present a series of photoabsorption and partial-ion-yield experiments on thionyl chloride, SOCl(2), at both the sulfur and chlorine K edges. The photoabsorption results exhibit better resolution than previously published data, leading to alternate spectral assignments for some of the features, particularly in the Rydberg-series region. Based on measured fragmentation patterns, we suggest the LUMO, of a(') character, is delocalized over the entire molecular skeleton. Unusual behavior of the S(2 +) fragment hints at a relatively localized bond rupture (the S-O bond below the S K edge and the S-Cl bonds below the Cl K edge) following excitation to some of the higher lying intermediate states.