Dual-wavelength Raman spectroscopy approach for studying fluid-phase equilibria using a single laser

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Spectroscopy

Background:

• Investigating multiphase fluid mixtures requires advanced analytical techniques.
• Simultaneous analysis of both vapor and liquid phases presents significant challenges.
• Raman spectroscopy offers molecular-level insights but requires optimized setups for complex systems.

Purpose of the Study:

• To propose a novel Raman spectroscopy setup for the simultaneous investigation of multiphase fluid mixtures.
• To enhance signal intensity for vapor phase analysis and enable high-resolution liquid phase studies.
• To facilitate accurate mixture composition determination and the study of molecular physics phenomena.

Main Methods:

• Utilizing a frequency-doubled Nd:YAG laser.
• Separating the laser output into 532 nm (for vapor phase Raman signals) and 1064 nm (for liquid phase Raman scattering).
• Employing a dual-wavelength excitation strategy within a single Raman spectroscopy setup.

Main Results:

• Achieved sufficient signal intensity from the low-density vapor phase for composition determination.
• Enabled the recording of high-resolution spectra from the liquid phase.
• Demonstrated the capability for simultaneous concentration measurements and molecular physics studies.

Conclusions:

• The proposed Raman spectroscopy setup is effective for comprehensive analysis of multiphase fluid mixtures.
• This dual-wavelength approach overcomes limitations of single-wavelength methods for complex fluid systems.
• The technique provides a powerful tool for both chemical composition analysis and fundamental molecular studies.