He I Photoelectron Spectroscopic (PES) Study on the Electron Structure of Perchloric Acid, HOClO₃, and Fluorine Perchlorate, FOClO₃

Abstract

The He I photoelectron spectra (PES) of HOClO3 and FOClO3 are reported. The assignments of the PES bands are made on the basis of band shapes, relative band intensities, and the results of ab initio calculations using GAUSSIAN 94 at the 6-31G* basis set level. The two peaks (at 12.37 and 12.77 eV) in the first PES band of HOClO3 are designated as electron ionizations from HOMO 8a‘‘(25), SHOMO 7a‘‘(24), and 17a‘(23) orbitals, respectively, and they can be attributed to a Jahn−Teller effect on the largely lone-pair orbitals of three oxygen atoms in the ClO3 atomic group of HOClO3. The absence of splitting in the first PES band of FOClO3 centered near 13.20 eV is attributed to a loss of C 3 v symmetry in the ClO3 atomic group of FOClO3. This band is assigned to electron ionizations of the HOMO 9a‘‘(29), SHOMO 8a‘‘(28), and 20a‘(27) orbitals, in which the three oxygen atoms of the ClO3 atomic group of the FOClO3 molecule hold dominant weight.

Electronic Structure and Photoionization and Dissociation Processes of Bis(trifluoromethoxy)disulfurylperoxide, CF3OS(O)2OOS(O)2OCF3

“…The experimental apparatus used in this work has been described previously. , Briefly, the photoelectron and photoionization mass spectrometer consists of two parts: one part is the double-chamber UPS-II machine; another part is a time-of-flight mass spectrometer. The photoelectron spectrum was recorded on the double-chamber UPS-II machine which was built specifically to detect transient species at a resolution of about 30 meV, as indicated by the Ar + ( 2 P 2/3 ) photoelectron band. , Experimental vertical ionization energies are calibrated by simultaneous addition of a small amount of argon and methyl iodide to the sample. Mass analysis of ions is achieved with the time-of-flight mass analyzer mounted directly to the photoionization point.…”

“…The photoelectron spectrum was recorded on the double-chamber UPS-II machine which was built specifically to detect transient species at a resolution of about 30 meV, as indicated by the Ar + ( 2 P 2/3 ) photoelectron band. 19,20 Experimental vertical ionization energies are calibrated by simultaneous addition of a small amount of argon and methyl iodide to the sample. Mass analysis of ions is achieved with the time-of-flight mass analyzer mounted directly to the photoionization point.…”