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Type of Document	Dissertation
Author	Rice, Steven Frederick
URN	etd-03102005-155606
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-03102005-155606
Title	Optical spectroscopic studies of square planar d8 dimers
Degree	PhD
Option	Chemistry
Advisory Committee	Advisor Name Title Harry B. Gray Committee Chair
Keywords	none
Date of Defense	1982-02-03
Availability	unrestricted
Abstract NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The single crystal polarized absorption spectra of rhodium(I) diisocyanide dimers presented confirm the assignment of Mann and Gray for the intense visible absorption band as [...]. The structured [...] absorption band in [...] shows the [...] excited state to have a metal-metal vibrational frequency of 149 [...]. This is compared to the 85 [...] ground state frequency which results in the orbital assignment of this transition as [...]. The excited state has an internuclear bond distance .31 [...] shorter than that of the ground state. The bonding description obtained through the analysis of the spectra depicts a ground state that is formally nonbonding stabilized through configurational interaction with a low lying, strongly bonded excited state. The [...] state in these dimers has a pronounced phosphorescence with a 77K lifetime of 20 [milliseconds]. The quantum yields and lifetimes are very temperature sensitive with several 300K lifetimes of about 10 nsec. This temperature dependence, characteristic of a strong coupling limit, is interpreted in terms of a nonradiative pathway depopulating the [...] through another excited state associated with a [...] transition. A compound isoelectronic with these rhodium diisocyanides, [...], is shown to have a similar metal-metal interaction in both the ground and lowest excited states. Recent results regarding the low temperature photophysics of this compound have been verified and extended through an analysis of the vibronically structured [...] luminescence. The [...] state is demonstrated to have an internuclear distance of 2.71 [...], .21 [...] shorter than that of the ground state. The metal-metal vibrational frequency in the [...] is 155 [...], distinctly higher than the 110 [...] of the ground state.
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