Application of PAS for the Investigation of Overtones and Combinations in the near IR

Abstract

The photoacoustic spectrometer (PAS) used in the near IR region is shown to be useful for observing the combinations and overtones of strong IR fundamentals. Overtones and combinations of the carbonyls in Mo(CO)6, Ir4(CO)12, and [RhCl(CO)2]2 are observed. Carbonyl and ring (C—H, C—C) fundamental overtones and combinations from (C6H6)Cr(CO)3 are observed in the near IR. The near IR PAS is shown to be useful for analyzing surface constituents on silicon. An overtone and combination due to bound H2O is identified on silicon by comparison to the near IR PAS spectrum of H2O and D2O. The C—N overtone band due to ferro- and ferricyanide is observed in the near IR by PAS. The spectrum of ferricyanide deposited on silicon is used to identify the surface changes that occur on a silicon photoelectrochemical cell coated with ferricyanide.