High resolution spectroscopy and dynamics of weakly bound dimers /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | Gas phase Fourier transform spectroscopy was used to determine rotationally resolved vibrational transitions in the hydrogen bonded dimer HCN--HF. Excitations of all intermolecular degrees of freedom of the hydrogen bond up to the first overtone are reported. Also, the first rovibrationally resolved spectrum of a third overtone of a hydrogen bond is reported. Dynamical information determined from these spectra suggests that a possible mechanism that explains the mode-dependent predissociation dynamics of this complex involves effective energy transfer between the v[1] HF stretch and v[6]^1 high frequency bend and the observed radial-angular coupling as shown by the increase in intermolecular separation upon excitation of the bending vibration. The determined spectroscopic information was inverted to generate a simplified intermolecular potential of this complex by considering the degrees of freedom in which the large amplitude motion takes place. The inversion procedure assumes adiabatic separation of angular and radial degrees of freedom. This allows for modified vibrational RKR inversion of the spectroscopic data to give effective radial potentials that are then fitted to a R-fixed angular potential. The large and short range of the intermolecular separations are extrapolated under constraints that ensure proper behavior. The inverted potential is then tested by a variational calculation. The agreement between predicted and experimental frequencies, rotational constants, and intensities is presented. A variational calculation was also used to identify a previously unassigned series of rovibrational transitions in Ar--DCl. The H6(3) potential of Hutson was used to predict frequencies and intensities of rovibrational transitions in Ar--DCl. This calculation predicts that the 2v[2]^0Σ bend in Ar--DCl will have intensities that depend upon ΔJ. The R branch is predicted to be 12 times stronger than the P branch. This is a consequence of Coriolis coupling between this state and the v[2]^1π bend and the difference in transition dipole moment of both transitions. Based on the fact that in such weak complexes excitation of the diatomic does not change the intermolecular potential significantly, we extrapolate these predictions to assign the unidentified R branch as that belonging to the combination band v[1]+2v[2]^0. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemistry." |
| Physical Description: | xi, 119 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |