Formation and photofragmentation properties of isolated aromatic amino acid-silver cluster hybrids

The formation of isolated (Trp-2H)+Ag₉] ⁺ and (Tyr-2H)+Ag₉] ⁺ amino-acid-Ag₉ hybrids is reported. The photofragmentation yields of the aromatic amino acid-silver cluster hybrids, as well as those of the protonated tryptophan and tyrosine molecules (Trp+H]⁺ and Tyr+H]⁺) have been recorded. The fragmentation yields of the complexes are higher than the yields for Trp+H]⁺and Tyr+H]⁺ and present an extension of the fragmentation on the red side of the spectrum. The photofragmentation spectrum of Trp+Ag₉] ⁺ was recently reported Mitric et al., J. Chem. Phys. 127, 134301 (2007)]. While the optical spectra of substituted (Trp-2H)+Ag₉] ⁺ and non-substituted Trp+Ag₉] ⁺ complexes are very similar, a strong modification of the fragmentation channels between the two complexes is observed. The fragmentation channels are sensitive to the type of bonding in aromatic amino acid-silver cluster hybrids and can be used as fingerprints of structures.