Report of the Working Group on Carbon

Abstract

It was clear to members of the group that carbon is important in the interpretation of several spectral regions of cosmic dust: the UV region, primarily because of the 2200 Å interstellar band, the 3 to 15 µm IR region, because of various unidentified bands in this region (including those at 3.3, 6.2, 7.7, 8.8 and 11.3 µm), and the far infrared region because of the necessity of fitting emissivity observations in this region. Carbon may also be important in the visible for explaining diffuse interstellar bands (4430 Å, etc.) following tentative suggestions for explanations based on clusters of carbon atoms in linear chains or in poly cyclic carbon molecules. It has became more and more clear, however, that carbon is an extremely complicated and variable material. The first part of this summary expresses our concern for evaluating and describing the nature of carbon used in experiments. Following this, three significant problems are summarized and in the final section a list of recommended work that is needed is given.