Nawaz Qaisrani
(Johannes Gutenberg University, Germany)

Abstract: In this talk, I will discuss the microscopic interpretation of water pump-probe vibrational energy relaxation processes at the aqueous interfaces. What happens when extra vibrational energy is added to water?, using non-equilibrium ab-initio molecular dynamics simulations and novel descriptors based on the projected vibrational density of states, we are able to monitor the excess energy flow of the locally excited water vibrational modes (stretching, bending and liberation). We show that intermolecular energy dissipations are faster (~200 fs) when water molecules form a strong hydrogen bond network, such as in bulk. However, at the interface with reduced hydrogen bonding, the energy transport significantly slows down (~370 fs), depending on the different types of hydrogen bonds. Particularly, we explore the role of free OH bonds present at the interface for their slow energy relaxations compared to any other type of hydrogen bond interactions.
 

Zoom registration link:
https://zoom.us/meeting/register/tJAqf-yvpzwuHNN8redGZkO6p6HXPRiMbmLT