On the electronic structure of methyl butyrate and methyl valerate
Résumé
We present novel results of the analysis of the electronic structure of two aliphatic esters: methylbutyrate and methyl valerate. High-resolution photoabsorption spectra were collected and analyzed over the energy range 4.0–10.8 eV and showed for both the molecules not only a clear band of the HOMO to LUMO transition, but also vibronic structure associated with the first Rydberg-valence transition. Photoelectronspectra recorded from 9 to over 28 eV revealed many ionization states with the first adiabatic ionization energies found to be 9.977 eV and 9.959 eV for methyl butyrate and methyl valerate, respectively. Ab initio calculations have been performed in order to help assign the photoabsorption and photoelectron features.Photolysis life times in the atmosphere were calculated revealing that photolysis is not competitive overhydroxyl radical scavenging in the process of removal of these esters from the atmosphere.