Abstract: | The vibrational spectroscopy by way of vibrational sum-frequency generation (VSFG) has been made of formic acid adsorbed on MgO(001) surface and of n-alkyltrichlorosilanes chemisorbed on quartz plates. It was revealed that the species on the MgO surface was formate ion (HCOO+) with CH bonds standing vertical to the surface and that the different adsorption sites showed up on repeated cycles of adsorption-desorption processes. The results of chemisorbed films indicated that the g-t and/or g-t-g′ conformational scquences of n-alkyl chains occurred more frequently by the length of alkyl chain and that the surface hydroxyls, which are the sites of chemisorption, are ripped off by pre-exposure of substrate to oxygen plasma. |