Rovibrational State Mixing in Isolated Ground Electronic State Polyatomic Molecules
Kim, Hong Lae
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/70410
Description
Title
Rovibrational State Mixing in Isolated Ground Electronic State Polyatomic Molecules
Author(s)
Kim, Hong Lae
Issue Date
1988
Doctoral Committee Chair(s)
McDonald, J. Douglas
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
Abstract
Rovibrational state mixing in ground electronic state polyatomic molecules has been studied using infrared laser induced fluorescence and stimulated emission pumping (SEP) spectroscopy. Molecules are cooled and isolated in supersonic molecular beams. A relationship between state mixing, measured as our experimental dilution factor, and rovibrational bath state density has been investigated from a study of IR fluorescence in the C-H stretch fundamental region of a variety of organic molecules. A threshold density of about 70 rovibrational states per cm$\sp{-1}$ with the correct J and symmetry to couple has been found to ensure mixing regardless of molecular structure except for the case of acetylenic C-H stretches, which appear to be less effective in state mixing. Fluorescence from the C-H stretch fundamental region of acetaldehyde shows that the extent of state mixing scales linearly with J, and the measured relative energy apportioned among the vibrational modes in the molecule following excitation has been explained by applying a rovibrational state mixing model. SEP spectra of glyoxal are recorded in the regions of C = 0 stretch fundamental and its overtones by employing X($\sp1$A$\sb{\rm g}$) $\gets$ A($\sp1$A$\sb{\rm u}$) rovibronic transitions up to energies of 7000 cm$\sp{-1}$ above the ground vibrational state. At low energies, only isolated states are observed. However, at higher energies, clumps of eigenstates can be seen demonstrating extensive state mixing with the dense bath states in the region.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
