The electronic states of pyridine-N-oxide studied by VUV photoabsorption and ab initio configuration interaction
Michael H Palmer1, Søren Vrønning Hoffmann, Nykola C Jones
1School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, United Kingdom. m.h.palmer@ed.ac.uk
Abstract:
The first vacuum-ultraviolet absorption spectrum of pyridine-N-oxide has been obtained, and has led to the identification of nearly 30 Rydberg states. These states were identified by use of the vibrational envelope ("footprint") of the UV-photoelectron spectrum, and are based on the first to the third ionization energies (IE). The adiabatic IE order, central to the Rydberg state symmetry identification, is confirmed by multi-configuration SCF calculations as: 1(2)B1 < 1(2)B2 < 1(2)A2 < 2(2)B1. Several excited valence state equilibrium structures were determined by multi-configuration SCF and coupled cluster procedures. Multi-reference multi-root CI was used to calculate both Rydberg and valence state vertical excitation energies and oscillator strengths, which were correlated with the experimental measurements.
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