Computing Bulk Phase Resonance Raman Spectra from ab Initio Molecular Dynamics and Real-Time TDDFT

Area of Science:

• Computational chemistry
• Spectroscopy
• Materials science

Background:

• Resonance Raman (RR) spectroscopy is a powerful technique for molecular analysis.
• Simulating RR spectra of bulk systems, especially with solvent and anharmonic effects, is computationally challenging.
• Existing methods often struggle to capture the complexities of condensed-phase systems.

Purpose of the Study:

• To present a novel computational approach for calculating RR spectra of periodic bulk phase systems.
• To incorporate solvent influence and anharmonic effects into RR spectral simulations.
• To demonstrate the method's capability by simulating the RR spectrum of uracil in aqueous solution.

Main Methods:

• Utilizing real-time time-dependent density functional theory (RT-TDDFT).
• Employing ab initio molecular dynamics simulations.
• Calculating RR spectra for all relevant laser wavelengths in a single computational pass.

Main Results:

• Successfully computed the RR spectrum of uracil in aqueous solution.
• Achieved good agreement between simulated and experimental RR spectra.
• This marks the first successful simulation of a bulk phase RR spectrum.

Conclusions:

• The novel ab initio molecular dynamics approach is effective for simulating RR spectra of bulk systems.
• The method accurately accounts for solvent effects and anharmonicity.
• This work opens new avenues for theoretical investigations of condensed-phase spectroscopy.