Vacuum ultraviolet photoelectron spectroscopy of transient species. Part 14.—A study of the ground state of NF+via the ionization processes NF+(X2Π)â†� NF(X3Σ–, a1Δ)

Abstract

The NF radical has been investigated using vacuum ultraviolet photoelectron spectroscopy and ab initio molecular orbital calculations. The first accurate values for the adiabatic and vertical first ionization potentials have been measured as 12.26 ± 0.01 and 12.63 ± 0.01 eV, respectively, for NF in its ³Σ^– ground electronic state. Values have also been obtained for these processes for the ¹Δ excited state of NF. The difference between the two adiabatic ionization energies was found to be in excellent agreement with the a¹Δ–X³Σ^– separation determined by optical spectroscopy.

Since the ionization processes referred to above lead to a common X²Π state of NF⁺, analysis of the vibrational fine structure associated with the observed spectral bands allowed w_e and r_e for this ionic state to be determined as 1520 ± 40 cm^–1 and 1.180 ± 0.006 Å, respectively. The dissociation energy D_e for NF⁺(X²Π) was also estimated as 5.8 ± 0.3 eV.