title: Rotationally resolved electronic spectra of 1,2-dimethoxybenzene and the 1,2-dimethoxybenzene-water complex.
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.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Yi
authors.forename: Jason W
authors.initials: JW
authors.lastname: Ribblett
authors.forename: David W
authors.initials: DW
authors.lastname: Pratt
mesh_terms: D000840:Anisoles / Q000737:chemistry*; D006860:Hydrogen Bonding; D011789:Quantum Theory; D012399:Rotation; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods; D014732:Vibration; D014867:Water / Q000737:chemistry
chemical_list: D000840:Anisoles; D014867:Water; C005299:veratrole