Vibrational predissociation spectroscopy of hydrogen-bonded complexes in the 10 micron region

LaCosse, Jeffrey Paul

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https://hdl.handle.net/2142/18977 Copy

Description

Title

Vibrational predissociation spectroscopy of hydrogen-bonded complexes in the 10 micron region

Author(s)

LaCosse, Jeffrey Paul

Issue Date

1991

Doctoral Committee Chair(s)

Lisy, James M.

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Chemistry, Physical
• Physics, Molecular

Language

eng

Abstract

Vibrational predissociation spectroscopy of isotopomers of (CH$\sb3$OH)$\sb2$ and Ar(CH$\sb3$OH) were recorded in the 10 micron region, where the C-O stretching transition is located. Using the beam depletion technique, spectra were recorded for (CH$\sb3$OH)$\sb2$, (CH$\sb3$OD)$\sb2$,(CD$\sb3$OD)$\sb2$,(CH$\sb3$OH)(CH$ \sb3$OD),(CH$\sb3$OD)(CD$\sb3$OD),(CH$\sb3$OX)Ar (X = H,D) and (CD$\sb3$OD)Ar. It is observed that in the mixed dimers, complexes, the measured C-O transition frequencies are unchanged from their respective monomers. Time of flight measurements were also conducted to determine the translational temperature of the complexes. A band contour analysis was done to estimate the homogeneous and inhomogeneous contribution to the observed linewidths. All of the complexes except the ones containing CH$\sb3$OD methanol had a homogeneous contribution of no greater than 1 cm$\sp{-1}$. The complexes involving CH$\sb3$OD have a homogeneous width of less than 0.5 cm$\sp{-1}$. A transition dipole coupling model was studied to reveal that only 1 cm$\sp{-1}$ out of the 25 cm$\sp{-1}$ of splitting observed in (CH$\sb3$OH)$\sb2$ is due to dipole-dipole interactions. The model does not predict the isotopic shift in (CH$\sb3$OH)(CH$\sb3$OD) for either the donor or acceptor C-O stretching transition. Integral dissociation cross sections were also measured for the different species, with good agreement with a previous measurement by another group for (CH$\sb3$OH)$\sb2$. The measured integral dissociation cross sections for the various deuterated dimers decreased with the number of deuterium atoms within the complex. Preliminary studies of (CH$\sb3$NH$\sb2$)$\sb2$, Ar(CH$\sb3$NH$\sb2$), (CH$\sb3$CH$\sb2$OH)$\sb2$, Ar(CH$\sb3$CH$\sb2$OH), ((CH$\sb3$)$\sb3$COH)$\sb2$, Ar(1,4-dioxane), (1,4-dioxane)$\sb2$, Ar(d$\sb6$-acetone) and (d$\sb6$-acetone)$\sb2$ were also carried out in the 10 micron region.

Type of Resource

text

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http://hdl.handle.net/2142/18977

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Copyright 1991 LaCosse, Jeffrey Paul

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