Electronic transitions in mono-olefinic hydrocarbons

Abstract

This d is s e rta tio n is dedicated to my parents, Mr. and Mrs. Freddie H. Watson, S r., who have done so very much for me. C ertain ly they are due much of the c re d it for the completion of th is work. ACKNOWLEDGEMENT The author would like to take th is opportunity to thank his major professor, Dr. S.P. McGlynn, whose patience, encouragement and advice made the completion of th is work p o ssib le. A sp ecial thanks is due Mrs. Falba Simmons for her encouragement and her help with the computations. Thanks are due also to the members of Dr. McGlynn1s research group for th e ir many a ssista n c e s and for many f r u i t f u l discussions; Dr. A.T. Armstrong who pioneered MO c a lc u la tio n s in these la b o ra to rie s; members of the Chemistry Department fa c u lty , e s p e c ia lly Dr. J.H. Wharton fo r many inform ative research d iscu ssio n s; the Chemistry Department s ta f f , esp e c ia lly Mr. G.H. Sexton, Mr. E. Keel and Mr. L. Dunlap; Dr. B.B. Townsend and the Computer Center s t a f f ; Dr. H.B. W illiams; Mrs. Judy Brignac and Mrs. Lynn D eSille fo r th e i r many favors and kindnesses; and Harold M. Barnes, J r. fo r his frien d sh ip. This work was supported by the Atomic Energy Commission-Biology Branch under research grant AT-(40-1)-3018. F in an c ial a ssista n c e in the p rep aratio n of th is d is s e r ta tio n was provided by the Charles E. Coates Memorial Fund,of the Louisiana State U niversity Foundation donated by George H. Coates.

Through-Bond Interactions and the Localization of Excited-State Dynamics

“…To this end, the computed energy of the π3s state of CHE at 6.39 eV is in reasonable agreement with the spectroscopically determined value of 5.92 eV. 42 While the 7.76 eV excitation energy to the ππ* is somewhat higher than the absorption maximum near 6.89 eV, it is consistent with the large geometric relaxation expected on the excited state. The bright ππ* state (I = 0.658) will clearly have the largest oscillator strength, I, from the ground state for one photon absorption processes, but the significantly weaker 3s transition (I = 0.028) is also symmetry allowed.…”

Ultrafast non-adiabatic dynamics of methyl substituted ethylenes: The π3s Rydberg state

“…Upon increasing methylation, the origin of the π 3s←N transition shifts strongly to the red (as does the ionization potential), whereas the V←N transition maximum shifts only slightly to the red. 10,[13][14][15] As a result, the π 3s←N bands, which in ethylene lie fairly close to the V←N Franck-Condon (FC) maximum, move relatively further to the red with methylation, until in tetramethylethylene, they are clearly isolated from the V←N transition. For 1,2-dimethylethylene and trimethylethylene, the π 3s←N bands may be overlapped with the red edge of the strong V←N bands.…”

The α(C—C)/β(C—H) ratio of the primary processes in the 184.9 nm photolysis of gaseous cis- and trans-2-butene

“…q p i c a l rates of photon input in the cell are in the ranges (2-6) X l o i 3 or (6-10) X l o i 3 photons s-I. The absorption coefficients of the mercury line (184.9 nm) by olefins are very high (8). For example, at a pressure of 0.3 Torr, ca.…”

“…2A), one can extract the quantum yields of process [7], i.e. in the absence of a stabilizing process [8]: 'Traces of n-pentane were also observed: @ 5 0.01. tively. Thus, at first sight, it seems that the P(C-H) bond rupture (process [3]) is more important in cis-2-butene.…”

“…0 2 , @N0,02 (1 ,3-butadiene), and the quantum yield of process [22]. As far as +(process [8]) is concerned, it may be obtained from the sum of radical-radical reactions involving a-methallyl radicals:…”