Completely Computational Model Setup for Spectroscopic Techniques: The Ab Initio Molecular Dynamics Indirect Hard...

Area of Science:

• Spectroscopic analysis and computational chemistry.
• Quantitative chemical analysis and molecular modeling.

Background:

• Traditional spectroscopic quantification relies on pure compounds and known mixtures for calibration, which are often unavailable.
• Existing methods to address calibration gaps are not universally applicable, posing challenges for complex systems with unstable species.

Purpose of the Study:

• To develop a new calibration approach for physics-based spectral analysis using simulated spectra.
• To enable quantitative spectroscopic analysis of systems previously inaccessible due to calibration challenges.

Main Methods:

• Utilized *ab initio* molecular dynamics (AIMD) to simulate spectra.
• Applied simulated spectra to calibrate the indirect hard modeling (IHM) method, creating the AIMD-IHM approach.
• Analyzed Raman spectra of ternary hydrogen-bonding mixtures (acetone, methanol, ethanol).

Main Results:

• AIMD-IHM pure-component models and calibration coefficients closely matched experimental results.
• Achieved prediction errors below 5% for mixture compositions without experimental calibration input.
• Demonstrated the method's efficacy on challenging ternary mixtures.

Conclusions:

• The AIMD-IHM approach provides accurate quantitative spectroscopic analysis without experimental calibration.
• This method is applicable to systems with unstable species, overcoming previous limitations.
• The approach shows potential for extension to other spectroscopic techniques like infrared and NMR spectroscopy.