Electron momentum spectroscopy study of amantadine: binding energy spectra and valence orbital electron density distributions

The electron binding energy spectrum and valence orbital electron momentum density distributions of amantadine (1-aminoadamantane), an important anti-viral and anti-Parkinsonian drug, have been measured by electron momentum spectroscopy. Theoretical momentum distributions, calculated at the 6-311++G{*}{*} and AUG-CC-PVTZ levels within the target Hartree-Fock and also the target Kohn-Sham density functional theory approximations, show good agreement with the experimental results. The results for amantadine are also compared with those for the parent molecule, adamantane, reported earlier (Chem. Phys. 253 (2000) 41). Based on the comparison tentative assignments of the valence region ionization bands of amantadine have been made. (C) 2000 Elsevier Science B.V. All rights reserved.