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Some factors which affect the spin densitites of protons, with particular emphasis on the β-protons of cyclobutenyl


Steadman, Vivian Louise (1967) Some factors which affect the spin densitites of protons, with particular emphasis on the β-protons of cyclobutenyl. Master's thesis, California Institute of Technology. doi:10.7907/6S0F-1650.


Both first-order and variational valence bond calculations were made to estimate the ESR hyperfine splittings of the β-protons of cyclobutenyl. The ESR spectrum of the radical has not been obtained; but on the basis of these calculations, it is anticipated that the β-proton splittings will be large and in the range 42g to 101g. The first-order results indicate considerably larger splittings than the variational calculation; this situation was shown to be in marked contrast with another valence bond calculation on a free radical containing β-protons. Possible inequality in the β-proton splittings of cyclobutenyl at low temperatures was also discussed. The dependence of the spin densities of β-protons on π-electron excitation energies (in appropriate free radicals) was discovered and was shown to reduce the size of the β-proton hyperfine splittings. The agreement with experiment was satisfactory. The transformation between the vector-coupling states for an eight electron system and its canonical states was obtained. The canonical states were found to be especially amenable to computer computations, involving the non-overlap, empirical valence bond theory. The reasons for the suitability of the use of vector-coupling functions in configuration interaction in the valence bond theory were discussed. A case was presented in which it appeared desirable to distribute the antisymmetrical spatial components of the ground-state wave function somewhat differently in space than that of the symmetrical spatial components. An anomaly in the ESR spectra of irradiated benzene was deduced from theoretical considerations.

Item Type:Thesis (Master's thesis)
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • McLachlan, Andrew D. (advisor)
  • McKoy, Basil Vincent (advisor)
Thesis Committee:
  • Chan, Sunney I.
  • Goddard, William A., III
Defense Date:14 December 1966
Record Number:CaltechTHESIS:05072010-160004325
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5788
Deposited By: Tony Diaz
Deposited On:18 Aug 2010 18:41
Last Modified:21 Dec 2019 03:04

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