Full Assignment of Ab-Initio Raman Spectra at Finite Temperatures Using Wannier Polarizabilities: Application to...

Area of Science:

• Computational chemistry
• Spectroscopy
• Materials science

Background:

• Accurate interpretation of Raman spectra is crucial for understanding molecular structure and dynamics.
• Simulating Raman spectra from first principles often presents challenges in assigning peaks to specific vibrational modes.

Purpose of the Study:

• To develop and demonstrate a method for fully assigning simulated Raman peaks to specific molecular vibrations.
• To enable precise interpretation of Raman spectra at finite temperatures.

Main Methods:

• Utilized a novel method for simulating Raman spectra based on ab initio molecular dynamics.
• Expressed total system polarizability as a sum over Wannier polarizabilities.
• Calculated partial Raman activities from correlations between different types of Wannier functions.

Main Results:

• Successfully demonstrated the full assignment of simulated Raman peaks to specific vibrations.
• Applied the method to cyclohexane in the gas phase, achieving complete peak assignment.
• Distinguished Wannier functions based on their spatial spread for detailed analysis.

Conclusions:

• The developed method provides a robust way to ascribe simulated Raman peaks to specific vibrational modes.
• This technique enhances the predictive power of computational spectroscopy for molecular systems.
• Offers a pathway for detailed structural and dynamic analysis of molecules through Raman spectroscopy.