title: Potassium-intercalated H2Pc films: alkali-induced electronic and geometrical modifications.
abstract: X-ray spectroscopy studies of potassium intercalated metal-free phthalocyanine multilayers adsorbed on Al(110) have been undertaken. Photoelectron spectroscopy measurements show the presence of several charge states of the molecules upon K intercalation, due to a charge transfer from the alkali. In addition, the comparison of valence band photoemission spectra with the density functional theory calculations of the density of states of the H(2)Pc(-) anion indicates a filling of the formerly lowest unoccupied molecular orbital by charge transfer from the alkali. This is further confirmed by x-ray absorption spectroscopy (XAS) studies, which show a decreased density of unoccupied states. XAS measurements in different experimental geometries reveal that the molecules in the pristine film are standing upright on the surface or are only slightly tilted away from the surface normal but upon K intercalation, the molecular orientation is changed in that the tilt angle of the molecules increases.
authors.affiliation: Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Nilson
authors.forename: J
authors.initials: J
authors.lastname: Åhlund
authors.forename: M-N
authors.initials: MN
authors.lastname: Shariati
authors.forename: J
authors.initials: J
authors.lastname: Schiessling
authors.forename: P
authors.initials: P
authors.lastname: Palmgren
authors.forename: B
authors.initials: B
authors.lastname: Brena
authors.forename: E
authors.initials: E
authors.lastname: Göthelid
authors.forename: F
authors.initials: F
authors.lastname: Hennies
authors.forename: Y
authors.initials: Y
authors.lastname: Huismans
authors.forename: F
authors.initials: F
authors.lastname: Evangelista
authors.forename: P
authors.initials: P
authors.lastname: Rudolf
authors.forename: M
authors.initials: M
authors.lastname: Göthelid
authors.forename: N
authors.initials: N
authors.lastname: Mårtensson
authors.forename: C
authors.initials: C
authors.lastname: Puglia