Minchul Yang

Sample mounting and transfer mechanism for in situ IR-visible sum frequency generation vibrational spectroscopy in high-pressure ultrahigh vacuum system

We developed a sample mounting and transfer mechanism for studying heterogeneous catalytic reactions in a high-pressure ultrahigh vacuum system. The system is optimized for the use of sum frequency generation vibrational spectroscopy to probe surface species in situ during the reactions. The system allows wide-ranging working conditions: a pressure range between 4×10−10 and 760 Torr and a temperature range between 200 and 1200 K. Rigid and reproducible sample positioning as well as precise temperature control can be achieved by compact designs of a sample holder and a sample mount incorporating ultrahigh vacuum compatible plugs. The performance of the system is demonstrated here by monitoring surface intermediates over time during cyclohexene catalytic reactions using a Pt(111) single crystal and sum frequency generation vibrational spectroscopy.