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Updated: Jun 9, 2026

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
Published on: October 18, 2018
Electronic structure and spectroscopy of ClSO
Tarek Trabelsi1, Joseph S Francisco2
1Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA.
Abstract:
Recent synchrotron photoionization mass spectrometry studies have identified ClSO+ as a prominent product in the VUV photochemistry of Cl2SO and revealed the vibronically structured near-threshold ionization of the ClSO radical. Motivated by these advances, we provide a focused, high-accuracy theoretical characterization of ClSO+. Coupled-cluster calculations including all-electron scalar-relativistic and explicitly correlated protocols yield equilibrium structures and benchmark adiabatic (9.47 eV) and vertical (9.67 eV) ionization energies for ClSO. The ClSO+ ground-state potential is predicted to be strongly bound, with a Cl-S bond dissociation energy of 3.21 eV at the CCSD(T)/aug-cc-pV(5+d)Z level. MRCI+Q and EOM-CCSD methods define the low-lying singlet manifold of ClSO+. We report rotational constants and IR intensities for key isotopologues, quantify geometry changes upon ionization, and predict vertical electronic excitations. This reveals a dominant allowed transition in the near-UV, alongside low-lying dark states that relax strongly along the Cl-S stretching coordinate. Our results provide a molecular framework for interpreting the threshold ionization spectra of ClSO and for assigning or anticipating ClSO+ features in VUV/UV experiments.
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