Note on the Ultraviolet Absorption Systems of Benzene Vapor

Abstract

An attempt has been made to give a coherent interpretation of the absorption systems of benzene vapor in the far ultraviolet including the Rydberg series. The following assignments are proposed: A forbidden transition of symmetry 1A1g→1B1u is suggested for the bands at 2050 to 1850A and an allowed 1A1g→1E—u transition for the much more intense bands at 1850 to 1650A. The continuous background in the latter region may possibly be due to a transition involving a C–H dissociation. The observed two Rydberg series can both be assigned to allowed transitions of symmetry 1A1g→1E—u.

New benzene absorption cross sections in the VUV, relevance for Titan’s upper atmosphere

“…Price and Walsh (1947) were convinced about this assignment both by the position of the band and by its accompanying vibrational pattern. They also suggested the overlaying continuous hump of absorption to come from C-H dissociation (also suggested by Nordheim et al, 1940). The 'shoulders' with maxima around 1781Å and 1804Å in our spectra were confirmed by Koch and Otto (1972) to be part of 425 the underlying valence transition.…”

“…Some of the series 430 converge to the first IE, others to the second IE at 11.45 eV (1083Å). The intensity of some of these Rydberg series definitely points to the fact that they are due to allowed transitions of symmetry (Nordheim et al, 1940).…”

The Primary Photochemical Process In Simple Ketones

“…The ratio of carbon monoxide yield to ethylene yield is 2.2 under all conditions, and polymer has been observed in the cell walls subsequent to photolysis. The reaction of two methylenes 2CH2 = C2H4 (74) has been excluded except possibly for conditions of high intensity such as flash photolysis (55).…”

Stephen B. Libby and Karl A. van Bibber (eds.): Edward Teller centennial symposium: modern physics and the scientific legacy of Edward Teller

“…A former director of the Los Alamos Laboratory, Siegfried S. Hecker, described how after decades of having been considered persona non grata, Teller was invited back to Los Alamos and how he reemerged there (pp. [4][5][6][7][8][9][10][11][12]. Hecker describes the amusing analogy between the rivalry between Los Alamos and Livermore on the one hand, and between the Soviet Arzamas-16 and Chelyabinsk-70, on the other.…”

“…For the readers of Structural Chemistry, it is especially relevant that he and his co-authors published influential studies in what today would qualify as structural chemistry. They included studies on the thermodynamics of the reaction of acetylene plus hydrogen yielding ethane and gave realistic estimate of the barrier to internal rotation in ethane [1]; the famous Brunauer-Emmett-Teller equation describing multilayer adsorption on surfaces [2]; the stability of polyatomic molecules in degenerate electronic states, what later became known as the Jahn-Teller effect [3]; and on the controversial issue of benzene structure [4].…”