Thursday, September 14, 2017

Abstract-2D THz-THz-Raman Photon-Echo Spectroscopy of Molecular Vibrations in Liquid Bromoform

Ian A. FinneranRalph WelschMarco A. AllodiThomas Francis Miller, and Geoffrey A. Blake

Fundamental properties of molecular liquids are governed by long range interactions that most prominently manifest at terahertz (THz) frequencies. Here we report the detection of nonlinear THz photon-echo (rephasing) signals in liquid bromoform, using THz-THz-Raman spectroscopy. Together, the many observed signatures span frequencies from 0.5-8.5 THz, and result from couplings between thermally populated ladders of vibrational states. The strongest peaks in the spectrum are found to be electric dipole-forbidden and polarizability-allowed and may arise from nonlinearities in the intramolecular dipole moment surface driven by intermolecular interactions.

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