Efficient Semiclassical Dynamics for Vibronic Spectroscopy beyond Harmonic, Condon, and Zero-Temperature...

Area of Science:

• Physical Chemistry
• Computational Spectroscopy
• Molecular Dynamics

Background:

• Understanding light-induced molecular processes is crucial in physical chemistry.
• Vibrational substructure in spectra reveals photoinduced nuclear dynamics.
• Theoretical simulations are essential for interpreting spectral features.

Purpose of the Study:

• To review recent developments in computing vibrationally resolved electronic spectra.
• To present a theoretical approach that goes beyond standard approximations.
• To apply a combined method to calculate specific molecular absorption spectra.

Main Methods:

• Developed a theoretical approach combining on-the-fly ab initio thawed Gaussian approximation (TGA) for anharmonicity.
• Integrated thermo-field dynamics (TFD) to include non-zero temperature effects.
• Incorporated Herzberg-Teller (HT) corrections for non-Condon effects.

Main Results:

• Successfully computed vibrationally resolved electronic spectra beyond common approximations.
• The combined method accounts for anharmonicity, temperature, and non-Condon effects.
• Applied the method to calculate the S₁ ← S₀ and S₂ ← S₀ absorption spectra of azulene.

Conclusions:

• The developed computational method provides a more accurate way to simulate molecular spectra.
• This approach enhances the understanding of light-induced dynamics in molecular systems.
• The study demonstrates the successful application to the complex azulene molecule.