F. Pforte et al., Wave-vector-dependent symmetry analysis of a photoemission matrix element:The quasi-one-dimensional model system Cu(110)(2X1)O - art. no. 165405, PHYS REV B, 6316(16), 2001, pp. 5405
We derive orbital symmetry character from the study of peak intensities in
angle-resolved photoemission spectra taken at different incidence angles of
p-polarized light. Our method of analysis is tested at the oxygen-derived
antibonding band on the Cu(110)(2 x 1)O surface. This band has all initial
state energy E-i = -1.37 eV (T = 300 K) at the (Y) over bar point and shows
even symmetry with respect to the Gamma LUX mirror plane (along <(<Gamma>Y
)over bar>). The intensity analysis reveals that orbitals both of z-like (a
long surface normal) and y-like symmetry (y along the Cu-O chains) are mixe
d into this band. This interpretation is supported by several calculations.
The ground-state symmetry character was studied by a full-potential linear
ized augmented planewave method using a seven-layer supercell geometry. For
a direct comparison with the experimental intensities, photoemission spect
ra at the (Y) over bar point were calculated using the one-step model of ph
otoemission, Our results contribute to a long-standing discussion about the
orbital character of the even antibonding band. In particular we demonstra
te that this kind of intensity analysis can supply valuable information abo
ut symmetry properties.