Signatures of Intra-/Intermolecular Vibrational Coupling in Halogenated Liquids Revealed by 2D Raman-THz Spectroscopy

Hybrid 2D Raman-THz spectroscopy with the Raman-THz-THz (RTT) pulse sequence is used to explore the ultrafast intra- and intermolecular degrees of freedom of liquid bromoform (CHBr3) in the frequency range of 1-8 THz. Cross peaks observed in these 2D spectra are assigned to the coupling between the...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2019-07
Main Authors: Ciardi, Gustavo, Berger, Arian, Hamm, Peter, Shalit, Andrey
Format: Article
Language:English
Online Access:Get full text
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Summary:Hybrid 2D Raman-THz spectroscopy with the Raman-THz-THz (RTT) pulse sequence is used to explore the ultrafast intra- and intermolecular degrees of freedom of liquid bromoform (CHBr3) in the frequency range of 1-8 THz. Cross peaks observed in these 2D spectra are assigned to the coupling between the narrow intramolecular modes of the molecules and the much broader intermolecular degrees of freedom of the liquid. This assignment is based on the frequency position of the crosspeaks, however, it is shown that these frequency positions can be deduced accurately only when properly taking into account the convolution of the molecular response with the instrument response function of the experimental setup, the latter of which distorts the 2D spectra considerably. The assignment is backed up with additional experiments on diiodomethane (CH2I2), which has only one intramolecular mode in the frequency range of the experiment, and hence excludes the possibility of intramolecular couplings.
ISSN:1948-7185