Active control of chemical bond scission by site-specific core excitation

Ionic desorption in valence- and core- excited polymers: poly(vinyl chloride) and poly(vinylidene chloride)

“…It is believed that the main process governing ion desorption is the Auger process, which can be described in a simplified form as a relaxation process following excitation (resonant Auger) or ionization (normal Auger) of a core electron. Several examples are now known in which, following the ionization or excitation of an inner-shell electron and the corresponding relaxation through the Auger process, selective fragmentation is observed around the atom to which the inner-shell electron is closely associated [3][4][5][6][7][8][9]. In this paper we present photon stimulated ion desorption (PSID) spectra for poly(vinyl chloride) (PVC) and poly(vinylidene chloride) (PVDC), irradiated in the 21.21 to 310 eV photon energy range.…”

Photon stimulated ion desorption of condensed CO2 at ~ 85 K studied by synchrotron radiation

“…In the PSID model of Knotek and Feibelman [9,10], the multiple holes formed in the valence orbitals are created via intra-atomic or inter-atomic Auger transitions following corelevel excitation of adsorbate molecules. This is the well known Auger Stimulated Ion Desorption (ASID) mechanism that was studied extensively for molecules adsorbed or condensed on surfaces [11][12][13] as well as polymers [14][15][16][17][18]. In addition to such a direct process another (indirect) process, X-ray induced electron stimulated desorption (XESD) [19,20] is an important mechanism for desorption of species from a surface when no direct excitation of the top monolayers is produced.…”

Application of the equivalent‐core calculation to the Cl in core level on condensed SiCl4

“…The energies of virtual molecular orbitals for EICVOM calculations provide the position of core-excitation spectral lines, which can be compared to experimental results. The HF/6-311ϩϩG(d) calculation on the unoccupied orbital energies of the Cl core-excited state was performed on SiCl 3 Ar ϩ at the theoretical optimized geometry at the MP2/6-311ϩϩG(d) level on SiCl 4 . The negative values of the resulting unoccupied orbital energies were taken in this study as the term values of SiCl 4 .…”

“…The active control of chemical reactions may be achieved using quantum mechanical interference between the different pathways to determine outcomes, but this method is less well established [3]. Site-specific photochemical reactions by core excitation often are an alternative, complementary approach in chemical reaction control [2].…”

“…Site-specific photochemical reactions by core excitation often are an alternative, complementary approach in chemical reaction control [2]. Core electrons are generally localized at a specific atom in a molecule, and the differences in the binding energies for the different atoms are large enough to permit selective excitation of these atoms, or even of the same atom in chemically inequivalent environments within the same molecule [3]. If the energy deposited into the system is enough to produce resonant core level transition, which means localized excitation, the final step in this process will be the bond scission at the site of excitation [4].…”