Our main interests are reaction at solid/liquid, solid/gas, and solid/solid interfaces. IR spectroscopy, sum frequency generation (SFG), scanning probe microscopy (STM, AFM), laser spectroscopy, and electro-chemical techniques are combined for understanding the reactions at the molecular scale. Surface-enhanced IR (SEIRAS) developed in our laboratory enables fast time-resolved monitoring of the reactions. SFG is used to examined interfaces that are not easily accessible by IR.