Generalized bond polarizability model for more accurate atomistic modeling of Raman spectra

Area of Science:

• Computational chemistry
• Spectroscopy
• Materials science

Background:

• Raman spectroscopy is vital for molecular analysis.
• Calculating Raman spectra via molecular dynamics (MD) requires electronic polarizability.
• First-principles polarizability calculations are computationally intensive.

Purpose of the Study:

• To develop an accurate and computationally efficient atomistic model for electronic polarizability.
• To improve the modeling of Raman spectra using MD simulations.
• To overcome limitations of the traditional bond polarizability model (BPM).

Main Methods:

• Generalization of the bond polarizability model (BPM) to the generalized bond polarizability model (GBPM).
• Inclusion of terms for non-bonding atom pairs in the polarizability calculations.
• Validation against ab initio calculations and experimental data for molecules and BaTiO3.

Main Results:

• GBPM significantly enhances the accuracy of polarizability and Raman spectra calculations.
• High accuracy was achieved for various molecules (SO2, H2O, CH4, etc.) and ferroelectric BaTiO3.
• GBPM-based MD simulations of liquid water show improved agreement with experimental Raman spectra compared to BPM.

Conclusions:

• The generalized bond polarizability model (GBPM) offers a significant improvement over traditional models.
• GBPM enables accurate Raman spectra modeling in large-scale molecular dynamics simulations.
• GBPM provides a foundation for future developments in atomistic polarizability models.