I. The Emission and Absorption Spectra of Some Simple Molecules Trapped in Solid Rare Gases. II. Theory of Electronic Relaxation in the Solid Phase

Citation

Frosch, Robert Peter (1965) I. The Emission and Absorption Spectra of Some Simple Molecules Trapped in Solid Rare Gases. II. Theory of Electronic Relaxation in the Solid Phase. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/0F5C-F303. https://resolver.caltech.edu/CaltechETD:etd-04102003-103306

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. This thesis consists of two parts. The first part describes a study of the spectral properties of simple molecules trapped in liquid helium-cooled rare gas matrices and the equipment used in these studies. Measurements have been made of the phosphorescence lifetimes of C[subscript 6]H[subscript 6], C[subscript 6]D[subscript 6], C[subscript 10]H[subscript 8], and C[subscript 10]D[subscript 8] in at least one of the following solids: Ar, Kr, and Xe. The a[superscript 4]II [...] X[superscript 2]II and the B[superscript 2]II [...] X[superscript 2]II transitions of NO have been excited in Ar and Kr using x rays, and the resulting spectra measured and interpreted. The radiative lifetime of the NO quartet state has been measured in Ne, Ar, and Kr and found to be 156, 93, and 35 msec, respectively, in these solvents. C[subscript 2]H[subscript 2] and C[subscript 2]D[subscript 2] have been deposited in Ar, Kr, and Xe and submitted to x-ray damage. The well-known Swan bands of C[subscript 2] have been observed in both emission and absorption. Both the upper and lower states of the Swan system have [Delta]G values in the solid more than 10% greater than the gas phase values. In addition two new C[subscript 2] band systems with 0-0 bands in Ar at 22973 and 19619 cm[superscript -1], respectively, and with a common lower state have been tentatively identified. These systems apparently have not been reported in the gas phase. A transient system has been seen in the emission of a deposit of C[subscript 2]H[subscript 2] in Kr that may be due to HC[subscript 2]. Another series observed when C[subscript 2]H[subscript 2] is deposited in either Kr or Xe is apparently diacetylene phosphorescence. The second part of this thesis presents a theory of electronic relaxation in solid media. The theory indicates that rates of electronic relaxation in solids depend in an important way on the electronic coupling between initial and final states and on the vibrational overlap between initial and final states. The theory has been successful in explaining the effect of deuterium substitution and the heavy atom effect on relaxation rates. Only a small temperature effect is predicted.

Thesis Files