Electronic Properties and Dissociative Photoionization of Thiocyanates, Part III. The Effect of the Group’s Electronegativity in the Valence and Shallow-Core (Sulfur and Chlorine 2p) Regions of CCl 3 SCN and CCl 2 FSCN

RODRÍGUEZ PIRANI, LUCAS S.; DELLA VÉDOVA, CARLOS O.; GERONÉS, MARIANA; ROMANO, ROSANA M.; CAVASSO-FILHO, REINALDO; GE, MAOFA; MA, CHUNPING; ERBEN, MAURICIO F.

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Año: 2017 vol. 121 p. 9201 - 9210

1089-5639

Both photoelectron spectroscopy (PES) data andPhotoElectron-PhotoIon-Coincidence (PEPICO) spectra obtainedfrom a synchrotron facility have been used to examine theelectronic structure and the dissociative ionization of halomethylthiocyantes in the valence and shallow-core S 2p and Cl 2pregions. Two simple and closely related molecules, namely,CCl3SCN and CCl2FSCN, have been analyzed to assess the roleof halogen substitution in the electronic properties of thiocyanates.The assignment of the He(I) photoelectron spectra has beenachieved with the help of quantum chemical calculations at theouter-valence Green?s function (OVGF) level of approximation.The first ionization energies observed at 10.55 and 10.78 eV forCCl3SCN and CCl2FSCN, respectively, are assigned to ionizationprocesses from the sulfur lone pair orbital [n(S)]. When these molecules are compared with CX3SCN (X = H, Cl, F) species, alinear relationship between the vertical first ionization energy and electronegativity of CX3 group is observed. Irradiation ofCCl3SCN and CCl2FSCN with photons in the valence energy regions leads to the formation of CCl2X+ and CClXSCN+ ions (X= Cl or F). Additionally, the achievement of the fragmentation patterns and the total ion yield spectra obtained from thePEPICO data in the S 2p and Cl 2p regions and several dissociation channels can be inferred for the core-excited species by usingthe triple coincidence PEPIPICO (PhotoElectron-PhotoIon-PhotoIon-Coincidence) spectra.