| Abstract
| - Self-assembled monolayers (SAMs) of 4,4‘-terphenyl-substituted alkanethiols C6H5(C6H4)2(CH2)n-SH (TPn, n =1−6) on Au (111) substrates were studied using scanning tunneling microscopy (STM) and infrared reflection absorptionspectroscopy (IRRAS). When the SAMs were prepared at room temperature (RT, 298 K), TPn films (except TP2)exhibit an odd−even effect regarding both molecular orientation and packing density. For all investigated films, STMdata reveals the presence of a large degree of lateral order. In the case of odd-numbered TPns, the films revealed a(2√3 × √3)R30° molecular arrangement. For the even-numbered TP4 and TP6 SAMs, a c(5√3 × 3) rectangularunit cell was found. The packing density for the even-numbered TPn SAMs is 25% lower than that for the odd-numbered TPn SAMs. When the SAMs were prepared at 333 K, the even-numbered SAMs were found to formstructures with a significantly lower packing density. In the case of TP2, instead of the (2√3 × √3)R30° structureformed at room temperature, a c(5√3 × 3) structure was observed. For TP6 SAMs, the room-temperaturec(5√3 × 3) structure was replaced by a (6√3 × 2√3)R30° structure.
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