INVESTIGATION OF INTERNAL MOTION IN THE SYM CONFORMER OF 9-FLUORENEMETHANOL: A GAS PHASE HIGH RESOLUTION ELECTRONIC SPECTROSCOPY STUDY

Author Institution: Department of Chemistry, University of Pittsburgh, PA 15260; Department of Chemistry and Biomedical Engineering, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15217Last year, results were presented on the high resolution fluorescence excitation spectra of the S$_1\leftarrow$ S$_0$ origin transitions of two conformers of 9-fluorenemethanol (9FM). Theoretical calculations predicted two conformers, designated as symmetric and unsymmetric. Each of the two origin bands were uniquely assigned to a conformer. A splitting was observed in the origin band of the symmetric conformer, and possible explanations were presented for this splitting. One explanation involved a symmetric motion of the -OH group above the plane of the ring system, made possible by a concerted motion involving rotation about the C$_9$-C$_\alpha$ bond and rotation of oxygen about the C$_\alpha$-O bond. Spectra have now been taken of deuterated 9FM, with the -OH group being replaced by -OD. Analysis of these results will provide further information about the observed internal motion. The sym 9FM-D origin is found to be blue-shifted relative to 9FM and displays a reduced splitting