Recognition of biological systems by mass-resolved laser spectroscopy

Molecular clusters are non-covalent aggregates widely recognized as a new state of matter, whose properties are neither those of the individual constituents nor those of their condensed phases. Tailor made molecular clusters have proved to be ideal systems for modelling molecular recognition phenomena and their applications in many scientific fields interlocking the physical and life sciences are now well assessed. In the last few years, it has become possible, through the use of advanced laser techniques, to study the interactions between individual components of a cluster, produced by laser desorption. The studies were carried out developing laser spectroscopic methodologies, capable of characterizing molecular clusters and probing the chemical bond breaking and forming on an extremely short time scale. This paper deals with chiral recognition in gas phase clusters of biological interest through the application of the mass-resolved Resonant Two Photon Ionization (1 and 2 color R2PI) laser technique.The measurement of the spectroscopic shifts and of the fragmentation thresholds of diasteromeric clusters allows the determination of the nature of the interactions which control the formation of biological material and affect their stability and reactivity.