Fluorescence excitation and emission spectra of 1,5hyphen;dihydroxyanthraquinonehyphen;d2innhyphen;hexane at 10 K

摘要

The fluorescence excitation, between 430 and 505 nm, and emission, between 505 and 725 nm, spectra innhyphen;hexane of 1,5hyphen;dihydroxyanthraquinonehyphen;d0and hyphen;d2at 10 K have been measured. Dual excitation and emission associated to excited state proton transfer were observed. Apart from the long wavelength emission, well resolved vibrational structures were obtained. A remarkable spectral shift (684 cmminus;1) of the origin of the high frequency transition was observed upon deuteration. The energy gaps between the transition origins both in excitation and emission as well as the isotopic shifts of the origins, were interpreted in terms of Lippincottndash;Schroeder asymmetric double minimum potential functions along the OH coordinate. An extra fluorescence occurs in the low frequency range, vanishing upon deuteration. It was explained as due to the ngr;(OH) stretching mode of the high frequency emission enhanced via vibronic coupling between the two ground states.