The Open University ’ s repository of research publications and other research outputs Electronic state spectroscopy of methyl formate

The Open University's repository of research publications and other research outputs Electronic state spectroscopy of methyl formate probed by high resolution VUV photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations Journal Article (2010). Electronic state spectroscopy of methyl formate probed by high resolution VUV photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations. Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online's data policy on reuse of materials please consult the policies page. The first ab initio calculations of the vertical excitation energies and oscillator strengths are presented for the neutral electronic transitions of methyl formate, C 2 H 4 O 2. The highest resolution VUV photoabsorption spectrum of the molecule yet reported is presented over the wavelength range 115 to 310 nm (10.8 to 4.0 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new theoretical results. The calculations have been carried out to determine the excitation energies of the lowest energy ionic states of methyl formate and are compared with a newly recorded He(I) photoelectron spectrum (10.4 to 17.0 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross-sections have been used to calculate the photolysis lifetime of methyl formate in the upper stratosphere (20–50 km).