OH-stretching spectra of various vapour phase species were recorded to investigate hydrogen bonding. The species studied include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, acetylacetone, hexafluoroacetylacetone and the complex formed in the heterogeneous mixture of methanol and trimethylamine. The spectra range from the infrared, near infrared to visible wavelengths. The main focus of this study is in the near infrared region, in which the OH-stretching overtones are dominant.
The near infrared and visible spectrum of formic acid has been recorded to investigate coupling across bonds, specifically a resonance occurring between OH- and CH-stretching vibrations. The same resonance was also observed in the spectrum of 1,2-ethanediol. The spectra of deuterated isotopomers of formic acid and 1,2-ethanediol were recorded to experimentally verify the resonance.
The inherently weak nature of the vibrational overtone transitions required sensitive spectroscopic techniques to observe the spectra. The spectra were recorded with conventional long path length absorption spectroscopy and intracavity laser photoacoustic spectroscopy.
Anharmonic oscillator local mode calculations of the OH-stretching transitions were performed to simulate the observed spectra. These calculations require calculation of potential energy surfaces and dipole moment functions. Simulated spectra obtained with highly correlated ab initio methods and large basis sets have yielded the best agreement with observation.
| Identifer | oai:union.ndltd.org:ADTP/217379 |
| Date | January 2006 |
| Creators | Howard, Daryl L., n/a |
| Publisher | University of Otago. Department of Chemistry |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://policy01.otago.ac.nz/policies/FMPro?-db=policies.fm&-format=viewpolicy.html&-lay=viewpolicy&-sortfield=Title&Type=Academic&-recid=33025&-find), Copyright Daryl L. Howard |
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