The IR spectra of DCOOH and HCOOD crystals at low temperatures

We show the IR spectra of HCOOD and DCOOH crystals in the region 1000–3000 cm⁻¹ at 7, 77 and 125 K. This article is a complement to previous articles which described spectra of HCOOH and DCOOD crystals recorded in the same conditions. In this article we also compare the results obtained on the four isotopic species and specially focus our attention on a comparison of the moments or order 0, 1 and 2 of the v_O---H…O (O---H…O) and v_O---D…O bands. Furthermore, we precise some experimental aspects, particularly those concerning polarization effects. In the following paper, we shall deduce from the first moments the relative importance of the different anharmonicities governing the stretching motion of the H or D atoms in the H- or D---bonds.