Infrared Spectrum of Anthracene-d10

The infrared spectrum of anthracene-d10 is reported with the electric vector of the plane-polarized incident light parallel to all three crystal axes; thus the c-polarized spectrum is recorded for the first time. The measurements extend from 2000 to ∼ 50 cm−1; the single-crystal samples used were too thick to transmit radiation in the strongly absorbing region near 2260 cm−1 so that little new data are available concerning the CD stretching fundamentals. However, a fairly complete assignment of the molecular fundamentals at lower energy is presented, based on the criteria of line strength and polarization, and the product rule. A comparison with calculated frequencies and some earlier experimental assignments is given.