Electronic states of the fluorophore 9,10-bis(phenylethynyl)anthracene (BPEA): A synchrotron radiation linear dichroism investigation

The electronic transitions of 9,10-bis(phenylethynyl)anthracene (BPEA) were investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy in the range 20,000–58,000 cm^–1 (500–170 nm) on molecular samples aligned in stretched polyethylene. The investigation was supported by variable temperature spectroscopy and by quantum chemical calculations in the LCOAO and TD-DFT models. The combined experimental and theoretical evidence leads to characterization of several previously unobserved transitions and provides a revised polarization analysis of the visible absorption band of BPEA.