Formation of a Ti–Cu(111) single atom alloy: Structure and CO binding

A single atom Ti–Cu(111) surface alloy can be generated by depositing small amounts of Ti onto Cu(111) at slightly elevated temperatures (?500 to 600 K). Scanning tunneling microscopy shows that Ti-rich islands covered a Cu layer form preferentially on ascending step edges during deposition below about 400 K but replaces these between 500 and K, producing an in the brims steps. Larger partially Cu-covered Ti-containing also terraces 300 700 K. After exposure CO low temperatures, reflection absorption infrared spectroscopy (RAIRS) reveals distinct C–O stretch bands 2102 2050 cm?1 attributed adsorbed domains vs sites alloy. Calculations using density functional theory (DFT) suggest lower frequency band originates specifically from isolated atoms predicts higher for above subsurface ensembles. DFT further adsorbs flat-lying configurations contiguous structures with more than one thus such should not observed RAIRS. The ability generate will provide future opportunities investigate chemistry promoted representative early transition metal dopant host surface.