Ionization potentials of heteroalkenes: A comparative study

International audienceMethanimine, methylenephosphine and methylenearsine have been prepared in the gas phase and the gaseous flow has been analyzed by spectroscopy. Photoelectron spectra have been recorded and we report here a comparative study on these spectra. This comparison has been extended to the corresponding derivatives with a triple bond: hydrogen cyanide and methylidynephosphine. Estimation by theoretical calculations of the ionization potentials of the unknown methylidynearsine has been proposed. Copyright © 2004 John Wiley & Sons, Ltd

First synthesis and characterization by mass spectrometry and UV-photoelectron spectroscopy of methylenearsane

International audienceIn a vacuum gas-solid reaction (VGSR; see scheme), the kinetically unstable methylenearsane was synthesized by dehydrohalogenation of gaseous chloromethylarsane on solid sodium carbonate and characterized in the gas phase by mass spectrometry and UV photoelectron spectroscopy. A new approach to theoretically evaluate ionization potentials is also demonstrated

Adenine tautomers: relative stabilities, ionization energies, and mismatch with cytosine

In this study, we have investigated 12 tautomers of the DNA base adenine at the BP86/TZ2P and BP86/ QZ4P levels of density functional theory. The vertical and adiabatic ionization energies of all tautomers were determined as the difference in energy between the radical cation and the corresponding neutral system. Furthermore, an evaluation is made for the eigenvalue spectra calculated with the SAOP functional, which is shown to lead to substantial improvements for orbital energies compared to BP86. We have also explored the correlations between the Kohn-Sham orbitals of the different tautomers at the BP86/QZ4P and SAOP/QZ4P levels. Finally, we discuss implications of the existence of the tautomeric forms of adenine for the DNA replication