return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Vibrations > Bad Calculations > Bad vib. Calc. vs exp. OR Resources > Bad Calculations > Vibrations > Bad vib. Calc. vs exp.

Bad vibrational frequency predictions

Calculated frequencies that differ from experiment by more than 400 cm-1 or have a ratio with experiment outside of 0.7 to 1.2 are listed

Calculated vibrational frequencies ("theory" in table) are calculated at MP2=FULL/cc-pV(T+d)Z
Calculated values were scaled by 0.9481.

Species Name mode Symmetry Experiment Theory difference ratio
HCN+ hydrogen cyanide cation 1 Σ 3050 3511 461 0.869
HCN+ hydrogen cyanide cation 2 Σ 1800 2699 899 0.667
CH3COOCH3 methyl acetate 27 A" 110 66 -44 1.675
C4H9N Pyrrolidine 36 A" 65 49 -16 1.335
C5H8 Cyclopentene 18 A' 254 179 -75 1.416
CH2NN diazomethane 6 B1 406 227 -179 1.788
C2H3NO3 Oxamic acid 3 A' 2600 3454 854 0.753
C2H3NO3 Oxamic acid 21 A" 162 67 -95 2.423
C5H8 1,4-Pentadiene 16 A 137 292 155 0.469
CO+ carbon monoxide cation 1 Σ 2214 2727 513 0.812
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 212 68 0.679
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 347 -109 1.314
CN Cyano radical 1 Σ 2069 2757 689 0.750
C2H Ethynyl radical 2 Σ 1841 2403 562 0.766
C2H Ethynyl radical 3 Π 372 778 407 0.477
CH3OO methylperoxy radical 12 A" 170 122 -48 1.394
O2+ diatomic oxygen cation 1 Σg 1906 1445 -461 1.319
OClO Chlorine dioxide 3 B2 1110 2259 1149 0.491
N2O3 Dinitrogen trioxide 9 A" 63 161 98 0.391
C3 carbon trimer 3 Πu 63 179 115 0.355
SiP Silicon monophosphide 1 Σ 616 1055 439 0.584
PS phosphorus sulfide 1 Σ 739 1136 397 0.651
AlO Aluminum monoxide 1 Σ 979 399 -581 2.455
SCN thiocyanato radical 1 Σ 1942 2372 430 0.819
ClOO chloroperoxy radical 2 A' 414 1052 639 0.393
ClOO chloroperoxy radical 3 A' 201 475 274 0.424
H2POH Phosphinous acid 9 A" 375 257 -118 1.460