Ultrafast spectroscopy of model biological membranes

Abstract

In this PhD thesis, I have described the novel time-resolved sum-frequency generation (TR-SFG) spectroscopic technique that I developed during the course of my PhD research and used it study the ultrafast vibrational, structural and orientational dynamics of water molecules at model biological membranes - key towards understanding the dynamic hydrogen-bonded structure of water interfacial with model biological membranes. The TR-SFG technique developed, follows a pump-probe experimental scheme whereby an intense IR laser pulse excites molecular vibrations and the Sum Frequency Generation (SFG) pulse is used to probe the dynamics of surface molecules as they relax back to the ground state, as a function of the time delay between the excitation and probe pulses. The rate and mechanism of vibrational relaxation (lifetime dynamics) helps in understanding the effects of local molecular structure and hydrogen bonding around these surface molecules.