Bh. Torrie et Ba. Brown, RAMAN AND FAR-INFRARED SPECTRA OF FORMAMIDE AT TEMPERATURES DOWN TO 20-K, Journal of Raman spectroscopy, 25(2), 1994, pp. 183-187
The Raman and infrared wavenumbers of solid HCONH2 and DCOND2 were mea
sured at 20 K and high temperatures. More peaks were observed in both
the lattice and internal mode regions than were expected from the know
n structure, so the structure was redetermined. The resulting structur
e is in agreement with earlier determinations, so the extra peaks are
attributed to second-order effects produced by a large anharmonicity a
ssociated with the hydrogen bonds. Attempts to model the structural de
tails and the lattice dynamics had only a limited success, which may a
gain be attributed to anharmonic effects and to the basic inadequacies
of the models.