CaltechTHESIS
  A Caltech Library Service

Triplet exciton phenomena in benzene crystals

Citation

Nieman, George Carroll (1965) Triplet exciton phenomena in benzene crystals. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-04172003-162535

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.

Various aspects of the triplet exciton problem are investigated. By studying three-component isotopic mixed crystals of benzene it is shown that trap-to-trap triplet excitation migration is very rapid compared to singlet excitation migration. The closely related phenomenon of triplet-triplet annihilation is also discussed. Triplet-triplet annihilation accounts for the production of delayed fluorescence in molecular crystals and for the quenching of all phosphorescence from pure crystals of n-electron molecules.

By studying the small quasiresonance shifts introduced in the C[subscript 6]H[subscript 6] phosphorescence by changing the degree of deuteration of the benzene host crystal, the nearest neighbor "pairwise" triplet exciton matrix element ([beta]) for benzene is determined to be 12[...]1 cm[superscript -1]. This compares very well with the rough value of 9 cm[superscript -1] determined from excitation transfer studies and is only slightly less than that (18 cm[superscript -1] found for the singlet exciton interaction. These investigations also imply a new interpretation of the factor group splitting of the first singlet-singlet transition in crystalline benzene.

Optical evidence is presented which shows that benzene in its lowest triplet state is not a regular hexagon. Rather detailed phosphorescence spectra of various deuterated benzenes are also presented.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Robinson, G. Wilse
Thesis Committee:
  • Unknown, Unknown
Defense Date:7 August 1964
Record Number:CaltechETD:etd-04172003-162535
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-04172003-162535
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1404
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:18 Apr 2003
Last Modified:26 Dec 2012 02:37

Thesis Files

[img]
Preview
PDF (Nieman_gc_1965.pdf) - Final Version
See Usage Policy.

10Mb

Repository Staff Only: item control page