Prediction of the terahertz absorption features with a straightforward molecular dynamics method

Area of Science:

• Computational Chemistry
• Spectroscopy
• Materials Science

Background:

• Terahertz (THz) spectroscopy is valuable for material characterization.
• Predicting THz absorption spectra accurately can be computationally demanding.
• Existing methods may lack detailed spatial and temporal insights.

Purpose of the Study:

• To develop a computationally inexpensive yet accurate method for predicting THz absorption spectra.
• To validate the method by comparing simulation results with experimental measurements.
• To gain deeper insights into energy accumulation and molecular motion within the system.

Main Methods:

• Utilizing a fixed charge model with classic molecular dynamics (MD) calculations.
• Calculating THz absorption spectra for stearic acid B-form and C-form.
• Analyzing spatial and time-dependent energy accumulation in the molecular system.

Main Results:

• Successfully calculated THz absorption features for stearic acid B-form (1–3.4 THz) and C-form (1–2.7 THz).
• Demonstrated good agreement between simulated absorption peaks and experimental measurements.
• Validated the method by analyzing energy accumulation, confirming its core principles.

Conclusions:

• The proposed fixed charge MD method offers an accurate and computationally efficient alternative to ab initio calculations for THz spectrum prediction.
• This approach provides enhanced capabilities for analyzing energy distribution and local molecular dynamics compared to traditional MD simulations.