2D Raman-THz Spectroscopy of Binary CHBr3-MeOH Solvent Mixture

Hybrid 2D Raman-terahertz (THz) spectroscopy is used to measure the interactions between two solvents paired in the binary CHBr3-MeOH mixture in the frequency range of 1-7 THz. Changes in the cross peak signature are monitored, originating from the coupling of an intramolecular bending mode of CHBr3 to the collective intermolecular degrees of freedom of the mixture. The appearance of a new cross peak in the 2D spectrum measured for solvent mixture with MeOH molar fraction of 0.3 indicates a coupling to a new set of low-frequency modes formed due to the hydrogen bond interactions between the two solvents. This interpretation is supported by the measurement of the CHBr3-CS2 binary solvent mixture as well as by 1D absorption measurements of neat MeOH.

Automated summary

Hybrid 2D Raman-terahertz spectroscopy was utilized to investigate the interactions between two solvents in a binary CHBr3-MeOH mixture, revealing a coupling to a new set of low-frequency modes formed due to hydrogen bond interactions between the solvents.