Modeling multidimensional spectral lineshapes from first principles: application to water-solvated adenine

Area of Science:

• Computational Chemistry
• Spectroscopy
• Molecular Dynamics

Background:

• Spectral lineshape analysis is crucial for understanding molecular interactions.
• Existing methods often struggle to accurately model the complex interplay of static and dynamic disorder.
• Adenine's excited states are vital for biological processes and require detailed spectral characterization.

Purpose of the Study:

• To present a first-principles methodology for describing spectral lineshape.
• To elucidate the roles of static and dynamic disorder in shaping experimental optical spectroscopy signals.
• To compare two distinct simulation strategies for spectral lineshape prediction.

Main Methods:

• Developed a methodology based on first-principles calculations.
• Employed molecular dynamics (MD) simulations to capture solvent configurations.
• Compared two strategies: first-order perturbation and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations.

Main Results:

• Both simulation strategies yielded comparable results for adenine's spectral lineshape.
• The first-order perturbation method was found to be two orders of magnitude faster than the QM/MM approach.
• Successfully correlated various contributions (static/dynamic disorder, intra-/inter-molecular interactions) to experimental spectral broadening.

Conclusions:

• The proposed methodology accurately describes spectral lineshapes, offering insights into solvent-solute interactions.
• The faster first-order perturbation approach provides a computationally efficient alternative for spectral lineshape simulations.
• This work bridges the gap between theoretical predictions and experimental observations in optical spectroscopies.