Absorption Wavelength (image) American Institute of Physics Caption This graph shows absorption wavelength as a function of the number of carbon atoms in the silicon-terminated carbon chains SiC_(2n+1)H, for the extremely strong pi-pi electronic transitions. When the chain contains 13 or more carbon atoms - not significantly longer than carbon chains already known to exist in space - these strong transitions overlap with the spectral region occupied by the elusive diffuse interstellar bands. Credit D. Kokkin, ASU Usage Restrictions This image may be used only with appropriate caption and credit. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.