Table 1.

Overview on the unit cell parameters of structures of PTCDA on Cu(100) (column two) and on the (√2 × 2√2)R45° – 2O/Cu(100) surface (column three). For PTCDA/Cu(100) the parameters calculated for the commensurate (4√2 × 5√2)R45° structure derived by Schmidt et al. [8] are compared to those we derived from our STM data. γ₀ denotes the angle between the unit cell vectors a₀ and b₀, the lengths are a₀ and b₀, respectively. φ₀ denotes the angle between a₀ and the vector a_s of the unit cell of the Cu(100) surface along the direction (see Figure 4(d)). The last row of the table gives the superstructure matrices M₀ with respect to the substrate vectors of Cu(100).

	PTCDA/Cu(100)		PTCDA/O/Cu(100)
	(4√2 × 5√2)R45° [8]	Own STM results	STM results
a0 [Å]	14.46	14.5 ± 0.3	12.2 ± 0.3
b0 [Å]	18.08	18.0 ± 0.4	19.3 ± 0.4
γ0 [°]	90	89.9 ± 0.8	89.3 ± 1.2
φ0 [°]	45	45.2 ± 0.8	38.8 ± 0.8
M0