Speaker
Description
Spectral line shapes in the condensed phase contain information about various dynamical processes that modulate the transition energy, such as microscopic dynamics, inter- and intramolecular couplings. In this talk I will explore and describe the role of different physical phenomena that arise from the peculiarities of dissipative dynamics in multidimensional spectra. The methodology will be illustrated by calculating multidimensional signals for water in 2D infrared, 2D THz-Raman, and 2D IR-Raman spectra obtained from an equilibrium-non-equilibrium hybrid MD simulation algorithm. These signals are analyzed in terms of anharmonicity and nonlinear polarizability of vibrational modes using a Brownian oscillator (BO) model with linear-linear (LL) and square-linear (SL) system-bath interactions from the quantum hierarchical Fokker-Planck equations approach for non-Markovian noise. All characteristic 2D profiles of the signals obtained from MD are reproduced by the LL+SL BO model, indicating that this model captures the essential features of the inter- and intra-molecular motion.
