As part of an investigation of intramolecular energy transfer in jet-cooled 1B2u benzene, an extensive study of one photon 1B2u↔1A1g spectroscopy has been carried out. Our data lead to an assignment for ν8 in the 1B2u state (1516 cm−1), to a number of new assignments involving activity in ν18 and ν4, and they show that many of the higher vibrational levels in the 1B2u manifold are mixed. The activities of components of combination levels with different vibrational angular momenta have been observed and used to resolve several controversies concerning assignments in the 1B2u↔1A1g spectrum of benzene.

Ketene (CH2CO) adsorption and reaction on Ru(001) were studied by high-resolution electron energy loss spectroscopy (HREELS), static secondary ion mass spectrometry (SSIMS), and temperature programmed desorption (TPD). Only H2, CO, and C02 are observed in TPD. At 105 K, low ketene exposures dissociate to CO and methylene and adsorb molecularly as an ?j1 23(C,C,0) species. At higher exposures ketene adsorbs molecularly as rj2(C,C). Above 200 K, adsorbed ketene hydrogenates to two distinct acyl species: t;2(C,Ó) acetaldehyde (CH3CHO), and 2(£,0) acetyl (CH3CO). Adsorbed acetate is also considered. The hydrogen required for hydrogenation is supplied from decomposition of CH2 and ketene. Above 200 K, ethylidyne (CCH3) is formed. Methylidyne (CH) and acetylide (CCH) are formed by decomposition of all the above oxygenate and hydrocarbon species. Dosing ketene on Ru(001) at 350 K, where CO accumulates, favors ethylidyne formation. The adsorbed CO stabilizes ethylidyne, which otherwise decomposes at 320 K. Dosing at 400 K, which is above the threshold of CO desorption, results in CH and CCH.

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The chemistry of ketene (CH2CO) on Ru(001) was studied by static secondary ion mass spectrometry (SSIMS) and temperature programmed desorption (TPD). Ketene adsorption at 105 K is both molecular and dissociative and leads to H2, CO, and C02, blit no hydrocarbons, in TPD. Between 200 and 250 K, molecular ketene is hydrogenated to adsorbed oxygenates, tj1 2(C,0) acetaldehyde (CH3CHO) and tj2(C,0) acetyl (CH3CO). The hydrogen is supplied by the decomposition of methylene, the latter produced by ketene decomposition. Hydrogenation to CH3CHO is favored at low coverages of ketene, while at high coverages, hydrogenation to CH3CO is favored. Preor postadsorbed H2 enhances the hydrogenation of ketene to CH3CHO but does not lead to any hydrocarbon desorption. Between 200 and 250 K, ethylidyne (CCH3) forms, particularly at high initial ketene coverages. During dosing at 350 K, ketene decomposes but only H2 desorbs. The accumulated adsorbed species include CO and CCH3. While dosing at 400 K, both CO and H2 desorb, significantly more ketene decomposes than at lower temperatures, and CCH and CH accumulate.