Photoelectron and photoionization spectroscopy of weakly bound aluminum–methylamine complexes

Abstract

Aluminum–methylamine complexes are produced in pulsed molecular beams. Their electronic spectra are obtained using threshold photoionization and zero-electron-kinetic-energy photoelectron spectroscopies and interpreted using density functional and ab initio calculations. The photoelectron spectra reveal ground electronic states and intermolecular and ligand-based vibrations of Al–NHn(CH3)3−n and Al+–NHn(CH3)3−n (n=0–2), adiabatic ionization energies of Al–NHn(CH3)3−n, and a low-lying excited electronic state of Al–NH2CH3. In addition, the spectroscopic measurements and theoretical calculations show strong methyl substitution effects on the ionization energies and metal–ligand binding. Striking spectral differences are discovered between these aluminum complexes and previously studied gallium and indium analogues.