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I. Spectroscopic evidence for slow vibrational relaxation in excited electronic states of diatomics in rare gas solids. II. Static crystal field effects in the electronic spectra of isotopically mixed benzene crystals

Citation

Tinti, Dino Sabatino (1968) I. Spectroscopic evidence for slow vibrational relaxation in excited electronic states of diatomics in rare gas solids. II. Static crystal field effects in the electronic spectra of isotopically mixed benzene crystals. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Q9F2-8F38. https://resolver.caltech.edu/CaltechTHESIS:03182014-134017900

Abstract

Part I

Studies of vibrational relaxation in excited electronic states of simple diatomic molecules trapped in solid rare-gas matrices at low temperatures are reported. The relaxation is investigated by monitoring the emission intensity from vibrational levels of the excited electronic state to vibrational levels of the ground electronic state. The emission was in all cases excited by bombardment of the doped rare-gas solid with X-rays.

The diatomics studied and the band systems seen are: N2, Vegard-Kaplan and Second Positive systems; O2, Herzberg system; OH and OD, A 2Σ+ - X2IIi system. The latter has been investigated only in solid Ne, where both emission and absorption spectra were recorded; observed fine structure has been partly interpreted in terms of slightly perturbed rotational motion in the solid. For N2, OH, and OD emission occurred from v' > 0, establishing a vibrational relaxation time in the excited electronic state of the order, of longer than, the electronic radiative lifetime. The relative emission intensity and decay times for different v' progressions in the Vegard-Kaplan system are found to depend on the rare-gas host and the N2 concentration, but are independent of temperature in the range 1.7°K to 30°K.

Part II

Static crystal field effects on the absorption, fluorescence, and phosphorescence spectra of isotopically mixed benzene crystals were investigated. Evidence is presented which demonstrate that in the crystal the ground, lowest excited singlet, and lowest triplet states of the guest deviate from hexagonal symmetry. The deviation appears largest in the lowest triplet state and may be due to an intrinsic instability of the 3B1u state. High resolution absorption and phospho- rescence spectra are reported and analyzed in terms of site-splitting of degenerate vibrations and orientational effects. The guest phosphorescence lifetime for various benzene isotopes in C6D6 and sym-C6H3D3 hosts is presented and discussed.

Item Type:Thesis (Dissertation (Ph.D.))
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):
  • Robinson, G. Wilse
Thesis Committee:
  • Unknown, Unknown
Defense Date:29 September 1967
Funders:
Funding AgencyGrant Number
CaltechUNSPECIFIED
NASAUNSPECIFIED
Atomic Energy CommisionUNSPECIFIED
NSFUNSPECIFIED
Army Research Office (ARO)UNSPECIFIED
Record Number:CaltechTHESIS:03182014-134017900
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:03182014-134017900
DOI:10.7907/Q9F2-8F38
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8142
Collection:CaltechTHESIS
Deposited By: Benjamin Perez
Deposited On:18 Mar 2014 22:01
Last Modified:21 Dec 2019 04:32

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