Multistate vibronic interactions in difluorobenzene radical cations. II. Quantum dynamical simulations

Area of Science:

• Theoretical chemistry
• Quantum dynamics
• Spectroscopy

Background:

• Difluorobenzene radical cations exhibit complex electronic structures.
• Understanding their vibronic dynamics is crucial for predicting photochemical behavior.

Purpose of the Study:

• Investigate the multistate vibronic dynamics in the X-D electronic states of difluorobenzene radical cations.
• Analyze the impact of nonadiabatic interactions on photoelectron spectral envelopes and internal conversion processes.

Main Methods:

• Ab initio quantum dynamical approach using wave-packet propagation.
• Multiconfiguration time-dependent Hartree (MCTDH) method.
• Inclusion of five coupled electronic potential energy surfaces and 10-11 vibrational degrees of freedom.

Main Results:

• Nonadiabatic interactions restructure photoelectron spectral envelopes.
• Ultrafast internal conversion occurs on femtosecond to picosecond timescales.
• The meta-isomer shows weaker interactions between electronic state sets compared to ortho- and para-isomers.

Conclusions:

• Nonadiabatic coupling strongly influences the electronic and fluorescence dynamics of difluorobenzene radical cations.
• Isomeric differences in vibronic coupling affect internal conversion pathways.
• Findings provide insights into the photophysics of fluorinated benzene radical cations.