Abstract

The influence of torsional disorder around the ethynyl π-bridges of a linear D-π-A-π-D molecule on the nature of its S1 excited state was investigated using ultrafast time-resolved infrared spectroscopy. By tuning the pump wavelength throughout the S1 ← S0 absorption band, subpopulations with different extents of asymmetry could be excited. In nonpolar solvents, the equilibrated S1 state is symmetric and quadrupolar independently of the initial degree of distortion. Photoexcitation of distorted molecules is followed by planarization and symmetrization of the S1 state. Excited-state symmetry breaking is only observed in polar environments, where the equilibrated S1 state has a strong dipolar character. However, neither the extent nor the rate of symmetry breaking are enhanced in an initially distorted molecule. They are only determined by the polarity and the dynamic properties of the solvent.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.