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Updated: Aug 6, 2026

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Rotationally resolved electronic spectra of 1,2-dimethoxybenzene and the 1,2-dimethoxybenzene-water complex
John T Yi1, Jason W Ribblett, David W Pratt
1Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Abstract:
Rotationally resolved S(1) <-- S(0) electronic spectra of 1,2-dimethoxybenzene (DMB) and its water complex have been observed and assigned. The derived values of the rotational constants show that the bare molecule has a planar heavy-atom structure with trans-disposed methoxy groups in its ground and excited electronic states. The transition of DMB is polarized along the b-axis bisecting the methoxy groups, demonstrating that its S(1) state is an (1)L(b) state. Higher energy bands of DMB are also polarized along the b-axis and have been tentatively assigned to different vibrational modes of the (1)L(b) state. The water complex origin appears 127 cm(-1) to the blue of the bare molecule origin. Analyses of the high resolution spectra of DMB/H(2)O and DMB/D(2)O suggest that the water molecule is attached via two O-H...O hydrogen bonds to the methoxy groups in both electronic states. A tunneling motion of the attached water molecule is revealed by a splitting of these spectra into two subbands. Potential barriers to this motion have been determined.
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