An analysis and an interpretation of the reported photo-electron spectra of the nitrate anion, NO3−

Abstract

The traditional photoelectron (PE) spectrum and the spectrum measured by the modern method, slow photoelectron velocity-map imaging of a cryogenically cooled ion (cryo-SEVI), of the nitrate anion (NO₃⁻) reported by the Neumark group have been concurrently analyzed using traditional theories. According to the Wigner threshold law, the dependences of the anisotropy parameter, β(ε), and the photo-detachment (PD) cross-section, σ(ε), on the electron kinetic energy (ε) have been analyzed consistently. The observed β(ε) values are analyzed using the Cooper–Zare (CZ) and Wigner–Bethe–Cooper–Zare (WBCZ) formulations, the latter of which derives from the CZ formulation and the Wigner threshold law. The analyses show that the photoelectrons (PEs) from the bands terminating at the vibrationless and ν₄ fundamental levels of the NO₃ system primarily exhibit d- and s-wave characters (i.e., l = 2 and = 0 components), respectively, while the band terminating at the ν₁ fundamental region (∼1050 cm⁻¹) has both s- and d-wave characters. The mixed characteristic of the band including the ν₁ fundamental is consistent with the results from laser spectroscopy of the electronic transition of the NO₃ neutral radical, where it has been found that the overtone with l = ±3 closely lies near the ν₁ fundamental.