Anales de la Asociación Química Argentina
Print version ISSN 0365-0375
ESTRADA, M. R.; ZAMARBIDE, G. N. and SANCHEZ-MARIN, J.. Theoretical study of the outer valence photoelectron spectra of methyl nitrite and fluoromethyl nitrite. An. Asoc. Quím. Argent. [online]. 2006, vol.94, n.1-3, pp. 81-94. ISSN 0365-0375.
The effect of the syn-anti conformational isomerism and fluorination of methyl nitrite on the ultraviolet photoelectron spectra of methyl nitrite is predicted on the basis of Outer Valence Green Function calculations using the 6-311++G** basis set. The conformational space of methyl nitrite and its single, di- and tri-fluoromethyl derivatives have been explored with MP2 and B3LYP-DFT approaches. Only the fluoro-methyl nitrite shows minima with geometries compatible with bound systems, therefore the OVGF study has been limited to methyl nitrite and fluoro-methyl nitrite. A procedure has been devised to represent simulated spectra starting from the OVGF data and the experimental UPS spectrum taken from the literature. The He I experimental spectrum has been assigned at the OVGF level and the simulated spectra are discussed. It is predicted that the syn-anti conformational isomerism will affect less the spectrum of the fluorinated system than that of the methyl nitrite. The effects of fluorination will be larger for the second peak than for the first. Fluorination brings about changes of the general shape (e.g., peak shifts, changes in gap widths, positions, etc.) of the low ionization energies of the spectrum.