Mass analyzed threshold ionization of hydrogen bonded clusters of biological molecules: the 3-methylindole·C6H6 complex

The mass analyzed threshold ionization (MATI) technique has been used for measuring the adiabatic ionization energy of the 3-methylindole·C6H6 cluster (58 018 cm−1) and the binding energies in its ground ionic (4448 cm−1) and ground neutral state (1775 cm−1). We compare our results with those recently obtained for the 3-methylindole·H2O and the indole·C6H6 cluster. The small influence of methylation on the binding energies confirms the πhydrogen bonding character in the 3-methylindole·C6H6 complex.