A SURVEY OF DIFFUSE INTERSTELLAR BANDS (3800-8680-ANGSTROM)

A systematic search for diffuse interstellar absorption bands in the s pectra of four reddened early type stars has resulted in the detection of 64 new bands and another 69 possible interstellar features. The su rvey covers the wavelength range from 3800 to 8680 angstrom, with 0.3 angstrom resolution, down to a sensitivity limit of about W/E(B-V)=0.0 08 angstrom/mag. The spectra are shown in full length in order to allo w a direct comparison with laboratory absorption spectra of candidate diffuse band carriers. Indeed, it is now possible to decide whether st ellar or telluric lines mask any diffuse band that is observed in the laboratory, as we show in an example. The example chosen is that of th e naphtalene ion, for which we report the detection of two predicted D IBs at 6521 and 6741 angstrom.