Time Domain Simulations of Single Molecule Raman Scattering

Area of Science:

• Chemical Physics
• Spectroscopy
• Computational Chemistry

Background:

• Nonequilibrium chemical phenomena are critical in advanced microscopy and spectroscopy.
• Understanding single molecule behavior requires accounting for dynamic processes.

Purpose of the Study:

• To investigate the role of nonequilibrium effects in single molecule Raman spectroscopy.
• To simulate and analyze Raman spectra of thiobenzonitrile (TBN) using ab initio molecular dynamics (AIMD).

Main Methods:

• Ab initio molecular dynamics (AIMD) simulations were employed.
• Raman spectra were simulated for thiobenzonitrile (TBN) using B3LYP/def2-TZVP.
• Ensemble-averaged spectra were computed from short AIMD trajectories (~60 ps total time).

Main Results:

• AIMD simulations successfully reproduced ensemble-averaged Raman spectra of TBN.
• Short trajectories (~3.3 ps) provided insights into single molecule spectral features.
• Molecular conformational flexibility and nonequilibrium phenomena were identified as key factors.

Conclusions:

• AIMD-based simulations are effective for studying single molecule Raman scattering.
• Accounting for molecular dynamics and conformational changes is essential for accurate single molecule spectroscopy.
• This approach enhances the interpretation of complex single molecule measurements.