Vibrational sum-frequency observation of synthetic diamonds

Sum-frequency generation (SFG) spectroscopy was applied to the study of pla sma hydrogenated diamond C(100) surface of a synthetic diamond. Two vibrati onal resonance peaks with the intensities strongly dependent on the polariz ation combinations of the visible and infrared beams were observed at 2899 and 2924 cm(-1). From the results of SFG measurements for various polarizat ion combinations, the 2899 and 2924 cm(-1) peaks were assigned, respectivel y, to the antisymmetric and symmetric CH stretching modes of HC-CH group on H/C(100)-2 x 1 surface. In addition, a strong background signal with an os cillatory profile was observed. (C) 2001 Elsevier Science B.V. All rights r eserved.