Time-Variable Chiroptical Vibrational Sum-Frequency Generation Spectroscopy of Chiral Chemical Solution

Area of Science:

• Spectroscopy
• Chiroptical Spectroscopy
• Nonlinear Optics

Background:

• Vibrational sum-frequency generation (VSFG) spectroscopy is a surface-specific technique valuable for characterizing chiral molecules in bulk liquids.
• Spectral congestion of chiroptical VSFG peaks with varying amplitudes and phases presents challenges in accurate spectroscopic parameter determination.

Purpose of the Study:

• To introduce and validate a time-variable infrared-visible chiroptical three-wave-mixing technique for precise spectroscopic parameter determination.
• To address the limitations of spectral congestion in analyzing chiral molecules using VSFG.

Main Methods:

• Employing a time-variable infrared-visible chiroptical three-wave-mixing approach.
• Measuring chiral VSFG, achiral VSFG, and interference spectra of bulk R-(+)-limonene liquid.
• Performing a global fitting analysis on time-variable spectra to extract accurate spectroscopic parameters.

Main Results:

• Successfully determined spectroscopic parameters of second-order vibrational response signals from chiral chemical liquids.
• Demonstrated the capability of the time-variable technique to resolve overlapping spectral features.
• Achieved accurate parameter determination despite spectral congestion.

Conclusions:

• The time-variable VSFG approach enables accurate spectroscopic parameter determination for chiral molecules in liquids.
• This technique offers enhanced spectral resolution and potential for background-free chiroptical characterization.
• The method is valuable for advancing the analysis of vibrational optical activity in chiral systems.