Solving the spectroscopic phase: imaging excited wave packets and extracting excited state potentials from...

Area of Science:

• Quantum Chemistry
• Molecular Spectroscopy
• Computational Chemistry

Background:

• Accurate determination of molecular potentials and transition dipole moments is crucial for understanding molecular behavior.
• Extracting these properties from experimental data, such as fluorescence line intensities, often faces challenges with data completeness and accuracy.

Purpose of the Study:

• To develop a novel inversion scheme for extracting transition-dipole amplitude signs from fluorescence line intensities.
• To demonstrate the scheme's capability in accurately determining excited state potentials and transition dipoles as a function of internuclear distance.
• To show the utility of the obtained amplitudes for characterizing time-evolving wave packets and extracting double minimum potentials.

Main Methods:

• An inversion scheme is developed to process fluorescence line intensities.
• The scheme derives transition-dipole amplitude signs, which are then used to calculate potentials and dipoles.
• The method is validated using the A((1)∑) and B((1)Π(u)) states of the Na(2) molecule, including scenarios with incomplete or uncertain data.

Main Results:

• The inversion scheme successfully obtains the signs of transition-dipole amplitudes.
• Highly accurate excited state potentials and transition dipoles are extracted as a function of internuclear displacements.
• The method reliably extracts phase and amplitude information of time-evolving wave packets.
• Successful extraction of double minimum potentials is demonstrated.

Conclusions:

• The developed inversion scheme provides a robust method for determining molecular properties from fluorescence data.
• The approach is accurate and reliable, even with incomplete or uncertain experimental data.
• The scheme is broadly applicable to polyatomic molecules for detailed electronic structure and dynamics studies.