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Fluorescence spectra and ab initio theoretical studies of HCOOH /

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dc.contributor.author Ioannoni, Francesca. en_US
dc.date.accessioned 2009-06-04T14:09:28Z
dc.date.available 2009-06-04T14:09:28Z
dc.date.issued 1989-06-04T14:09:28Z
dc.identifier.uri http://hdl.handle.net/10464/1555
dc.description.abstract A fluorescence excitation spectrum of formic acid monomer (HCOOH) , has been recorded in the 278-246 nm region and has been attributed to an n >7r* electron promotion in the anti conformer. The S^< S^ electronic origins of the HCOOH/HCOOD/DCOOH/DCOOD isotopomers were assigned to weak bands observed at 37431.5/37461.5/37445.5/37479.3 cm'''. From a band contour analysis of the 0°^ band of HCOOH, the rotational constants for the excited state were estimated: A'=1.8619, B'=0.4073, and C'=0.3730 cm'\ Four vibrational modes, 1/3(0=0), j/^(0-C=0) , J/g(C-H^^^) and i/,(0-H^yJ were observed in the spectrum. The activity of the antisymmetric aldehyde wagging and hydroxyl torsional modes in forming progressions is central to the analysis, leading to the conclusion that the two hydrogens are distorted from the molecular plane, 0-C=0, in the upper S. state. Ab initio calculations were performed at the 6-3 IG* SCF level using the Gaussian 86 system of programs to aid in the vibrational assignments. The computations show that the potential surface which describes the low frequency OH torsion (twisting motion) and the CH wagging (molecular inversion) motions is complex in the S^ excited electronic state. The OH and CH bonds were calculated to be twisted with respect to the 0-C=0 molecular frame by 63.66 and 4 5.76 degrees, respectively. The calculations predicted the existence of the second (syn) rotamer which is 338 cm'^ above the equilibrium configuration with OH and CH angles displaced from the plane by 47.91 and 41.32 degrees. en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Fluorescence spectroscopy. en_US
dc.subject X-ray spectroscopy. en_US
dc.subject Electronics. en_US
dc.subject Formic acid. en_US
dc.title Fluorescence spectra and ab initio theoretical studies of HCOOH / en_US
dc.type Electronic Thesis or Dissertation en_US
dc.degree.name M.Sc. Chemistry en_US
dc.degree.level Masters en_US
dc.contributor.department Department of Chemistry en_US
dc.degree.discipline Faculty of Mathematics and Science en_US


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