Exploring Non-covalent Interactions by Jet-Cooled Electronic and Vibrational Spectroscopy

Gas-phase laser spectroscopy in a supersonic jet is an important technique to probe the intrinsic nature and strength of weak non-covalent interactions present in molecular systems relevant to biology and materials. In this chapter, a brief review of supersonic expansion, laser desorption, time of flight mass spectrometry, and various laser spectroscopic techniques based on resonantly enhanced multiphoton ionization (REMPI) and laser-induced fluorescence (LIF) has been presented. Further, some representative results on the interplay between various non-covalent interactions, as well as the inherent nature and strength of an unconventional non-covalent interaction, namely Se hydrogen bonding interaction, have been described. An in-depth understanding of various non-covalent interactions is crucial for the optimum design of drugs and functional materials. The future of gas-phase laser spectroscopy lies in obtaining insight on the non-covalent interactions directly from the study of larger peptides or equivalent molecular systems.