Absorption and vibrational spectra of methylamine and its ions using quantum chemical methods

We present vibrational spectra of methylamine and its ions using the MP2 method and absorption spectra using time dependent density functional method. On the basis of these calculations electronic transitions of methylamine were successfully determined. We also have derived electron affinity and ionization potential for methylamine. The ionization potential 8.98 eV from this work is in excellent agreement with the experimental value of 9.04 eV. We found that like neutral methylamine, its cation also displays strong σ → σ∗ electronic transitions in the vacuum UV region whereas its anion shows strong electronic transitions in both the vacuum and far UV regions. The detection of methylamine in astronomical objects may benefit greatly from the accurate new data on its far-UV and near-IR lines.