Following photoexcitation of Cl 2p electrons to various resonances, the dissociation dynamics of ionic and excited neutral fragments of gaseous CH 2 Cl 2 was investigated by combined measurements of photon-induced ionic dissociation, x-ray absorption, and uv-visible dispersed fluorescence. The Cl 2p core-to-Rydberg excitations near the ionization threshold produce a notable enhancement of excited neutral fragments (C * and CH * ), which is attributed to the contribution from a shake-modified resonant Auger decay and postcollision interaction. The excitation Cl 2p → 10 a * 1 induces an enhanced yield of CH 2 + , possibly originating from fast dissociation via a strongly repulsive surface. The experimental results provide insight into the dissociation dynamics of ionic and excited neutral fragment production following core-level excitation.
State-specific photochemistry for SiCl4 adsorbed on Si(100) at ∼90 K following the Cl 2p and Si 2p core-level excitations has been investigated by photon-stimulated ion desorption, resonant photoemission, ion energy distribution, and soft x-ray absorption spectral measurements. The Cl+ photon-stimulated ion desorption spectrum and Cl L-edge x-ray absorption spectrum for condensed SiCl4 exhibit a clear dissimilarity unlike the other fragments, viz. SiCl3+, SiCl2+, SiCl+, and Si+. The Cl+ desorption yield shows a significant enhancement following the Cl 2p→8a1* excitation, while the Si 2p→8a1* excitation leads to the scarce enhancement of the Cl+ yield. The Cl+ ion energy distributions via the Cl 2p→8a1* excitation are shifted to higher energy (0.3–0.4 eV) compared to those via the Cl 2p→9t2* and Si 2p→8a1* excitations. The enhancement of the Cl+ desorption yield at the Cl(2p)−18a1* resonance is attributed to the higher ion escape energy. These results provide an insight into the comprehensive understanding of the state-selective fragmentation of molecules via core-level excitation.
Photon-stimulated ion desorption (PSID) from solid Si(CH3)2Cl2 following Cl 2p core-level excitation has been investigated along with the resonant photoemission spectra using synchrotron radiation. The Cl L23-edge total-electron yield spectrum of solid Si(CH3)2Cl2 mainly exhibits the Cl 2p→15a1*, Cl 2p→10b1* and shape resonance peaks. A significant dissimilarity between the Cl L23-edge total-electron yield spectrum and Cl+ PSID spectrum of solid Si(CH3)2Cl2 is observed. The desorption of atomic Cl+ ions is detected predominantly at the Cl 2p→15a1* excitation, while scarcely any Cl+ ions are observed following the Cl 2p→10b1* excitation and Cl 2p→shape resonance excitation. This indicates that the character of bound terminating orbital has a significant influence on the desorption processes. The enhanced Cl+ desorption yield at the Cl 2p→15a1* resonance is attributed to the the fast desorption process originating from the localization of the spectator electron in the strong antibonding orbital.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.