Infrared Spectrum of Anthracene Crystals

The infrared spectrum of anthracene is reported with the plane of the incident polarized light parallel to all three crystal axes. The measurements were extended to 50 cm^− 1; thus the $c$ polarized spectrum was recorded over a sufficient spectral range to cover all fundamentals. Some lattice modes and all the low‐frequency infrared‐active fundamentals (below about 600 cm^− 1) were firmly assigned. Some earlier misassignments were corrected and a more probable; though, in part, still uncertain, assignment of the infrared‐active fundamentals at higher energy was made.