The IR spectrum of the most stable diformate anion was calculated at the MP
2/6-311 + + G(3df, 3pd), RHF/6-311 + + G**, and B3PW91/6-311 + + G** levels
. The internal coordinates were defined for the diformate anion and used in
potential energy distribution (PED) analysis. The FED analysis of the theo
retical spectra form the basis for elucidation of the future matrix isolati
on IR spectra. (C) 1999 Elsevier Science B.V. All rights reserved.