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Compare vibrational frequencies in CCCBDB for C2H4O4 (Formic acid dimer)

MP2/6-31G*

18 11 26 13 55
Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency Scaled
Frequency
Harm.
diff
Fund.
diff
Symmetry Harmonic
Frequency
Fundamental
Frequency
Comment
1 Ag 3286 3099           
2 Ag 3180 2999   50 Ag   2949 C-H was 2
3 Ag 1770 1669   -1 Ag   1670 C=O was 3
4 Ag 1489 1404   -11 Ag   1415 C-O-H was 4
5 Ag 1437 1355   -20 Ag   1375 H-C-O was 5
6 Ag 1265 1193   -21 Ag   1214 C-O was 6
7 Ag 678 639   -38 Ag   677 O-C=O was 7
8 Ag 204 193           
9 Ag 167 158   21 Ag   137 ipb O-H.O was 9
10 Au 1110 1047   -3 Au   1050 opb C-H was 13
11 Au 965 910   -12 Au   922 opb O-H was 14
12 Au 173 163   -5 Au   168 opb O-H.O was 15
13 Au 71 67   -3 Au   69 twist was 16
14 Bg 1090 1028   -32 Bg   1060 opb C-H was 10
15 Bg 936 883           
16 Bg 267 252   22 Bg   230 opb O-H.O was 12
17 Bu 3371 3179   95 Bu   3084 O-H was 17
18 Bu 3176 2995   56 Bu   2939 C-H was 18
19 Bu 1821 1717   -29 Bu   1746 C=O was 19
20 Bu 1469 1386   -68 Bu   1454 C-O-H was 20
21 Bu 1421 1340   -24 Bu   1364 H-C-O was 21
22 Bu 1266 1194   -24 Bu   1218 C-O was 22
23 Bu 701 661   -37 Bu   698 O-C=O was 23
24 Bu 263 248   -20 Bu   268 O-H.O was 24
The calculated vibrational frequencies were scaled by 0.943

See section Calculated; Vibrations; Scale Factors; Set scaling factors to change the scale factors used here.
See section Calculated; Vibrations; Scale Factors; Calculate a scale factor to determine the least squares best scaling factor.
See section Calculated; Vibrations; Scale Factors; Scale factor uncertainty for information on where the above scaling factor is from.