Spectres de vibration des acides oxaliques. II.—Spectres infrarouge et Raman de la phase α des acides H2C2O4, D2C2O4, H2C218O4 et D2C218O4

Abstract The infrared and Raman spectra of β phase of H 2 C 2 O 4 , H 2 C 2 18 O 4 , D 2 C 2 O 4 , D 2 C 2 18 O 14 and HDC 2 O 4 isotopic species have been investigated at various temperatures (300-30 K) in the 4000-50 cm − range. All the expected ( K = 0) lattice modes have been assigned and the amplitudes of R′ x and R′ z librations have been calculated. An assignment for 17 intramolecular fundamentals out of the 18 expected is given. Most of these internal modes show a relatively strong correlation field splitting. The structure of the OH and OD stretching bands is discussed in some detail using the isotope and temperature shifts and the isotopic dilution technique.