Vacuum synthesis and determination of the ionization energies of different molecular orbitals for BrOBr and HOBr

Pure BrOBr and HOBr were synthesized in vacuum by heterogeneous reactions of the dried bromine vapor and Br2/H2O mixture vapors (5:1) with HgO, respectively, and then characterized by He I photoelectron spectroscopy (PES) and augmented by ab initio GAUSSIAN 2 and the outer valence Green's functional calculations. The first PE band at 10.26 eV with vibrational spacing 550±60 cm–1 and the second PE band at 11.23 eV with vibrational spacing 240±60 cm–1 are, respectively, assigned as ionizations of the electrons of the highest occupied molecular orbital (HOMO)(6b1(39)) and the SHOMO(13b2(38)) orbitals of BrOBr. The first PE band at 10.73 eV with vibrational spacing 750±60 cm–1 and the second PE band at 11.56 eV with vibrational spacing 650±60 cm–1 are, respectively, assigned as ionizations of the electrons of the HOMO(6a[double-prime](22)) and the SHOMO(16a[prime](21)) orbitals of HOBr. The study does not only provide vacuum synthesis conditions for preparing pure BrOBr and HOBr, but also provide experimental PES results along with theoretical ionization energies of different molecular orbitals for BrOBr and HOBr