Electronic Spectra of the Triacetylene Cation (HC 6 H ) and Protonated Triacetylene (HC 6 H 2 ) Tagged with Ar

Abstract

Polyacetylene cations (HC 2n H + ) play important roles in combustion processes and in the chemistry of planetary atmospheres and interstellar clouds. Here we report the electronic spectrum for the triacetylene cation (HC 6 H + ) recorded over the 300-610 nm range by photodissociating mass-selected ions tagged with argon atoms in a tandem mass spectrometer. The spectrum shows three band systems that are assigned to CH18508-IE1.gif (origin transition 16 665 cm -1 ), CH18508-IE2.gif (origin transition 23 916 cm -1 ), and CH18508-IE3.gif (origin transition 29 920 cm -1 ). Although the CH18508-IE4.gif band system is well known, the CH18508-IE5.gif and CH18508-IE6.gif band systems are observed fo..