The Gas Phase Spectrum of Cyclic C18and the Diffuse Interstellar Bands

• DOI: 10.1086/500110
• Publication Date: 2006-03-13T16:47:12Z
• Authors: John P. Maier; Andrey E. Bogusla...; Hongbin Ding; Gordon A. H. Walker; David A. Bohlender
• Keywords: 13. Climate action; 0103 physical sciences; 01 natural sciences

The gas phase spectrum of the cyclic C18 molecule recorded in the laboratory at a temperature typical of diffuse interstellar clouds is compared with absorption features toward ζ Oph and HD 204827 in the 5730-5934 A region. For the origin band at 5928.5 A an upper limit to the column density of ≤1.8 × 1011 cm-2 is inferred. The origin band pattern in the laboratory spectrum changes on lowering the internal temperature in the 100-20 K range and bears a striking resemblance to the observed structure of a number of DIBs at other wavelengths. This suggests that platelike molecules or ions, comprising a couple of dozen to hundred carbon atoms, could be responsible for some of the latter absorptions.