return to home page Computational Chemistry Comparison and Benchmark DataBase Release 21 (August 2020) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Vibrations > Bad Calculations > Bad Vib. HF vs MP2 OR Resources > Bad Calculations > Vibrations > Bad Vib. HF vs MP2

Bad Vibrational Frequency Predictions

Unscaled vibrational frequencies calculated at MP2/6-31G* are generally lower than frequencies calculated at HF/6-31G*. This page lists vibrational modes for which that is not true, which may be a warning of a vibrational mode for which the harmonic assumption is poor, or the calculation at HF or MP2 is a poor description of the molecule. The vibrational numbering may not align for all calculations. This will result in some molecules listed here for which the vibrational frequency calculations are reasonable. Click on an entry for a comparison of all the vibrational frequencies for that molecule at HF/6-31G* and MP2/6-31G*.
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
H2+ Hydrogen cation 1 Σg 2151 2995 0.7181 0.00 6.93 0.0000 1.01 1.01 1.0000
LiH+ lithium hydride cation 1 Σ 359 1560 0.2301 33.08 42.27 0.7826 1.13 1.13 1.0000
HeLi+ Helium Lithium cation 1 Σ 173 207 0.8345 55.59 55.40 1.0034 4.74 4.74 1.0000
NeH neon hydrogen 1 Σ 46 64 0.7159 0.00 0.00 0.1458 1.06 1.06 1.0000
NaH+ sodium hydride cation 1 Σ 229 1337 0.1716 6.61 57013.14 0.0001 1.05 1.05 1.0000
HCl- hydrogen chloride anion 1 Σ 70 91 0.7690 2.37 11.88 0.1997 1.04 1.04 1.0000
CuH Copper monohydride 1 Σ 1783 2302 0.7745 420.27 431.75 0.9734 1.02 1.02 1.0000
HBr- hydrogen bromide anion 1 Σ 150 193 0.7771 10.47 31.54 0.3319 1.02 1.02 1.0000
Li2+ lithium diatomic cation 1 Σg 260 325 0.8012 0.00 1.23 0.0000 7.02 7.02 1.0000
LiBe Lithium Beryllium 1 Σ 238 313 0.7594 66.55 173.70 0.3831 7.77 7.77 1.0000
Be2- Beryllium diatomic anion 1 Σg 357 505 0.7075 0.00 0.00   9.01 9.01 1.0000
Be2 Beryllium diatomic 1 Σg 36 694 0.0524 0.00 0.00   9.01 9.01 1.0000
B2 Boron diatomic 1 Σg 904 1353 0.6683 0.00 0.00   11.01 11.01 1.0000
B2+ Boron diatomic cation 1 Σg 403 1501 0.2686 0.00 0.00   11.01 11.01 1.0000
BC- boron monocarbide anion 1 Σ 1425 1657 0.8600 39.17 4.89 8.0132 11.46 11.46 1.0000
BC+ boron monocarbide cation 1 Σ 448 1647 0.2720 0.28 640.87 0.0004 11.46 11.46 1.0000
CN Cyano radical 1 Σ 1982 2863 0.6923 13.46 20.37 0.6607 12.85 12.85 1.0000
BN- boron nitride anion 1 Σ 1616 2218 0.7287 83.27 198.08 0.4204 12.15 12.15 1.0000
BN+ boron nitride cation 1 Σ 1535 2576 0.5957 46.36 2705.50 0.0171 12.15 12.15 1.0000
BeN- Beryllium mononitride anion 1 Σ 1379 3103 0.4445 271.51 149201.00 0.0018 10.47 10.47 1.0000
BeN+ Beryllium mononitride cation 1 Σ 886 1188 0.7460 1.02 258.98 0.0039 10.47 10.47 1.0000
CO+ carbon monoxide cation 1 Σ 2392 2887 0.8287 4.48 629.11 0.0071 13.44 13.44 1.0000
NO Nitric oxide 1 Σ 2221 3913 0.5676 69.50 2715.47 0.0256 14.87 14.87 1.0000
FO Oxygen monofluoride 1 Σ 1175 1544 0.7612 37.34 119.54 0.3123 17.24 17.24 1.0000
FO+ fluorine monoxide cation 1 Σ 1340 1745 0.7676 89.82 172.40 0.5210 17.24 17.24 1.0000
Ne2 Neon diatomic 1 Σg 78 105 0.7373 0.00 0.00   19.99 19.99 1.0000
LiNe+ Lithium Neon cation 1 Σ 258 289 0.8940 112.98 112.16 1.0073 8.44 8.44 1.0000
NaF+ sodium fluoride cation 1 Σ 158 180 0.8801 20.93 22.97 0.9115 20.62 20.62 1.0000
NaBe Sodium Beryllium 1 Σ 124 154 0.8068 5.57 41.65 0.1338 10.87 10.87 1.0000
NaO- sodium oxide anion 1 Σ 384 797 0.4812 109.93 311.24 0.3532 18.28 18.28 1.0000
NaO+ sodium oxide cation 1 Σ 58 89 0.6461 21.81 22.45 0.9712 18.28 18.28 1.0000
Na2+ sodium diatomic cation 1 Σg 121 431 0.2807 0.00 0.01 0.0000 22.99 22.99 1.0000
MgO magnesium oxide 1 Σ 768 1071 0.7170 115.76 1148.53 0.1008 18.45 18.45 1.0000
LiMg Lithium magnesium 1 Σ 95 109 0.8741 1.28 18.07 0.0708 8.35 8.35 1.0000
NaMg Sodium Magnesium 1 Σ 4 18 0.2044 0.00 0.07 0.0060 23.47 23.47 1.0000
Mg2- magnesium diatomic anion 1 Σg 79 158 0.5031 0.00 0.00   23.99 23.99 1.0000
MgN Magnesium Nitride 1 Σ 13 565 0.0226 0.01 40.13 0.0002 16.54 16.54 1.0000
BAl Boron Aluminum 1 Σ 649 760 0.8547 119.41 40.45 2.9520 13.29 13.29 1.0000
AlO+ aluminum monoxide cation 1 Σ 805 1352 0.5957 116.48 590.24 0.1973 18.85 18.85 1.0000
Al2 Aluminum diatomic 1 Σg 316 362 0.8740 0.00 0.00   26.98 26.98 1.0000
SiC- silicon monocarbide anion 1 Σ 766 934 0.8198 8.10 36.46 0.2221 14.48 14.48 1.0000
SiN Silicon nitride 1 Σ 915 1477 0.6196 41.88 359.23 0.1166 16.80 16.80 1.0000
SiN+ silicon mononitride cation 1 Σ 601 1241 0.4845 30.69 605.32 0.0507 16.80 16.80 1.0000
SiP Silicon monophosphide 1 Σ 468 1336 0.3505 0.03 65800.80 0.0000 29.32 29.32 1.0000
CP Carbon monophosphide 1 Σ 1011 1542 0.6552 2.36 1.49 1.5892 14.48 14.48 1.0000
PO Phosphorus monoxide 1 Σ 1404 4103 0.3422 68.38 91804.09 0.0007 19.15 19.15 1.0000
PN- phosphorus nitride anion 1 Σ 877 1312 0.6686 52.97 41.42 1.2787 16.88 16.88 1.0000
PN+ phosphorus nitride cation 1 Σ 758 1512 0.5010 66.96 72.35 0.9255 16.88 16.88 1.0000
BP Boron monophosphide 1 Σ 1008 1157 0.8715 7.49 120.58 0.0621 13.25 13.25 1.0000
AlP Aluminum monophosphide 1 Σ 404 484 0.8344 0.28 4.14 0.0667 28.70 28.70 1.0000
CS+ carbon monosulfide cation 1 Σ 1248 1454 0.8582 3.21 51.64 0.0622 14.47 14.47 1.0000
NS- nitrogen sulfide anion 1 Σ 863 1046 0.8249 50.85 0.17 291.7562 16.90 16.90 1.0000
NS Mononitrogen monosulfide 1 Σ 894 1486 0.6016 23.57 84.12 0.2802 16.90 16.90 1.0000
AlS Aluminum sulfide 1 Σ 615 707 0.8700 8.12 54.19 0.1499 29.06 29.06 1.0000
AlS+ aluminum monosulfide cation 1 Σ 567 730 0.7767 0.02 43.81 0.0005 29.06 29.06 1.0000
PS phosphorus sulfide 1 Σ 547 1040 0.5262 0.05 1208.57 0.0000 31.46 31.46 1.0000
SiS+ silicon monosulfide cation 1 Σ 690 925 0.7460 0.23 163.19 0.0014 29.71 29.71 1.0000
SO- sulfur monoxide anion 1 Σ 736 1157 0.6360 39.62 6.91 5.7310 19.19 19.19 1.0000
CCl- carbon monochloride anion 1 Σ 272 444 0.6138 127.71 94.39 1.3530 14.42 14.42 1.0000
LiCl+ lithium chloride cation 1 Σ 286 320 0.8921 140.43 134.94 1.0407 8.10 8.10 1.0000
NaCl+ sodium chloride cation 1 Σ 137 159 0.8612 33.09 32.10 1.0309 26.60 26.60 1.0000
ClF- clorine monofluoride anion 1 Σ 84 470 0.1786 20.38 11.87 1.7166 22.64 22.64 1.0000
NCl- nitrogen monochloride anion 1 Σ 375 581 0.6457 104.50 27.63 3.7818 16.90 16.90 1.0000
NCl+ nitrogen monochloride cation 1 Σ 748 1823 0.4101 2.24 1888.46 0.0012 16.90 16.90 1.0000
AlCl- aluminum monochloride anion 1 Σ 308 350 0.8803 115.35 94.52 1.2203 29.96 29.96 1.0000
BeCl- beryllium monochloride anion 1 Σ 447 530 0.8432 124.77 90.88 1.3729 10.63 10.63 1.0000
MgCl- magnesium monochloride anion 1 Σ 285 322 0.8856 74.21 53.41 1.3896 27.50 27.50 1.0000
ClO- chlorine monoxide anion 1 Σ 519 708 0.7329 48.32 0.65 73.9118 19.28 19.28 1.0000
ClO+ chlorine monoxide cation 1 Σ 1031 1391 0.7410 160.79 0.01 13399.2800 19.28 19.28 1.0000
BCl- boron monochloride anion 1 Σ 269 433 0.6225 171.90 143.38 1.1988 13.17 13.17 1.0000
Ar2 Argon diatomic 1 Σg 8 16 0.5156 0.00 0.00   39.96 39.96 1.0000
Ca2 Calcium diatomic 1 Σg 2 21 0.1156 0.00 0.00   39.96 39.96 1.0000
TiO Titanium monoxide 1 Σ 1137 1290 0.8816 267.38 976.28 0.2739 19.19 19.19 1.0000
VO Vanadium monoxide 1 Σ 597 2218 0.2690 20.64 13856.59 0.0015 19.13 19.13 1.0000
CuCl Copper monochloride 1 Σ 382 474 0.8051 42.05 54.95 0.7652 41.57 41.57 1.0000
Cu2 Copper diatomic 1 Σg 304 406 0.7480 0.00 0.00   62.93 62.93 1.0000
CuF Copper monofluoride 1 Σ 665 836 0.7955 88.95 118.93 0.7479 22.67 22.67 1.0000
ZnO zinc monoxide 1 Σ 673 1001 0.6725 49.30 391.67 0.1259 18.82 18.82 1.0000
GaO Gallium monoxide 1 Σ 632 707 0.8935 51.18 1.10 46.3689 18.70 18.70 1.0000
GaP Gallium monophosphide 1 Σ 326 389 0.8377 2.01 7.57 0.2651 37.35 37.35 1.0000
GaN Gallium mononitride 1 Σ 541 696 0.7782 11.82 224.76 0.0526 16.18 16.18 1.0000
AlGa Aluminum Gallium 1 Σ 218 252 0.8667 0.01 0.38 0.0162 32.56 32.56 1.0000
SiSe+ Silicon Monoselenide cation 1 Σ 572 771 0.7418 7.14 237.01 0.0301 33.65 33.65 1.0000
SeO- selenium monoxide anion 1 Σ 588 887 0.6630 0.17 91.84 0.0018 18.46 18.46 1.0000
BrCl+ bromine chloride cation 1 Σ 492 605 0.8130 19.00 40.11 0.4737 42.18 42.18 1.0000
BrF- bromine fluoride anion 1 Σ 93 495 0.1879 13.10 138.08 0.0949 22.28 22.28 1.0000
NBr nitrogen monobromide 1 Σ 594 729 0.8150 38.93 56.98 0.6833 15.98 15.98 1.0000
BrO- Bromine monoxide anion 1 Σ 493 644 0.7649 9.78 15.88 0.6159 18.48 18.48 1.0000
BrO Bromine monoxide 1 Σ 638 787 0.8107 2.55 4.40 0.5793 18.48 18.48 1.0000
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
H2S- Hydrogen sulfide anion 3 A' 75 243 0.3089 16.75 26.83 0.6243 1.06 1.04 1.0128
H2Ar H2 Ar dimer 3 Π 36 82 0.4384 0.00 0.00 0.6364 1.01 1.01 0.9999
H2Ar H2 Ar dimer 3 Π 36 82 0.4384 0.00 0.00 0.6364 1.01 1.01 0.9999
H2Ar H2 Ar dimer 2 Σ 30 51 0.5851 0.00 0.02 0.2019 1.06 1.06 1.0000
HCN+ hydrogen cyanide cation 2 Σ 2084 2959 0.7042 47.83 335.60 0.1425 5.53 1.25 4.4224
HCN+ hydrogen cyanide cation 1 Σ 3420 3969 0.8616 261.49 1.02 256.6901 1.17 4.24 0.2760
HNC+ hydrogen isocyanide cation 2 Σ 2177 2813 0.7737 26.66 55.79 0.4778 6.52 3.79 1.7223
HNC+ hydrogen isocyanide cation 3 Π 682 791 0.8633 165.76 168.00 0.9866 1.30 1.31 0.9935
HNC+ hydrogen isocyanide cation 3 Π 682 791 0.8633 165.76 168.00 0.9866 1.30 1.31 0.9935
NNH Dinitrogen monohydride 2 A' 2053 2827 0.7261 23.93 69.54 0.3441 11.95 1.71 6.9675
HNO+ Nitrosyl hydride cation 1 A' 3153 5303 0.5945 275.34 15141.45 0.0182 1.07 12.43 0.0864
HNO+ Nitrosyl hydride cation 2 A' 2037 2965 0.6869 34.70 396.09 0.0876 10.04 1.06 9.4460
NOH+ nitric oxide O-protonated 2 A' 1897 2166 0.8758 90.37 962.40 0.0939 12.95 14.32 0.9045
COH+ Carbon Monoxide, protonated 3 Π 126 317 0.3965 317.01 296.26 1.0700 1.27 1.27 0.9994
COH+ Carbon Monoxide, protonated 3 Π 126 317 0.3965 317.01 296.26 1.0700 1.27 1.27 0.9994
FHF- FHF- 2 Σu 1363 1606 0.8485 3073.70 2681.59 1.1462 1.03 1.03 1.0000
HNS- HNS- 3 A' 774 871 0.8888 17.00 37.93 0.4483 13.34 14.65 0.9105
HCS Thioformyl radical 2 A' 1032 1609 0.6419 0.90 296.82 0.0030 7.07 8.69 0.8135
HOCl+ hypochlorous acid cation 2 A' 1377 1957 0.7037 222.30 33743.62 0.0066 1.10 2.82 0.3919
HOCl+ hypochlorous acid cation 3 A' 1087 1326 0.8203 9.65 4789.50 0.0020 14.04 1.54 9.1099
HOBr+ Hypobromous acid cation 3 A' 851 1006 0.8458 36.99 1.24 29.8987 15.20 6.71 2.2639
C3 carbon trimer 3 Πu 153 176 0.8704 2.13 20.17 0.1058 12.00 12.00 1.0000
C3 carbon trimer 3 Πu 153 176 0.8704 2.13 20.17 0.1058 12.00 12.00 1.0000
C3+ carbon trimer cation 3 Πu 145i 290 -0.4999 17.74 1.28 13.8740 12.00 12.00 1.0000
C3+ carbon trimer cation 3 Πu 145i 290 -0.4999 17.74 1.28 13.8740 12.00 12.00 1.0000
C3+ carbon trimer cation 2 Σu 2496 2909 0.8580 3932.18 9050.54 0.4345 12.00 12.00 1.0000
NCN NCN 3 Πu 376 501 0.7506 13.67 24.22 0.5646 12.54 12.54 1.0000
NCN NCN 3 Πu 376 501 0.7506 13.67 24.22 0.5646 12.54 12.54 1.0000
LiCN lithium cyanide 3 A' 107 220 0.4863 30.55 20.40 1.4976 10.32 10.57 0.9764
N3 azide radical 2 Σu 1705 6209 0.2746 654.41 0.00   14.00 14.00 1.0000
CO2+ Carbon dioxide cation 3 Πu 426 580 0.7356 41.87 32.69 1.2807 12.88 12.88 1.0000
N2O- Nitrous oxide anion 1 A' 1434 3032 0.4728 69.14 1231.17 0.0562 14.03 14.01 1.0014
N2O- Nitrous oxide anion 3 A' 555 717 0.7735 6.97 26.03 0.2679 14.53 14.44 1.0062
N2O+ Nitrous oxide cation 1 Σ 2140 3290 0.6504 1.06 56.88 0.0187 14.00 14.01 0.9996
N2O+ Nitrous oxide cation 3 Π 509 643 0.7917 3.58 1.73 2.0709 14.24 14.23 1.0002
N2O+ Nitrous oxide cation 3 Π 421 500 0.8433 4.53 2.21 2.0490 14.24 14.23 1.0002
O3- Ozone anion 3 B2 926i 158 -5.8570 3110.40 13247.90 0.2348 15.99 15.99 1.0000
O3- Ozone anion 1 A1 1221 1368 0.8926 2.14 5.85 0.3664 15.99 15.99 1.0000
O3 Ozone 3 B2 1454 2379 0.6112 786.17 1482.27 0.5304 15.99 15.99 1.0000
O3+ Ozone cation 3 B2 1207 2986 0.4043 614.36 203.60 3.0175 15.99 15.99 1.0000
NO2 Nitrogen dioxide 3 B2 1881 2272 0.8279 757.20 1971.90 0.3840 14.62 14.62 0.9995
BO2+ Boron dioxide cation 3 Πu 178 333 0.5355 48.08 150.59 0.3193 11.96 11.96 1.0000
BO2+ Boron dioxide cation 3 Πu 178 333 0.5355 48.08 150.59 0.3193 11.96 11.96 1.0000
BO2+ Boron dioxide cation 2 Σu 938 1244 0.7543 4597.61 3001.15 1.5320 11.96 11.96 1.0000
NCO isocyanato radical 1 Σ 1959 2509 0.7805 20.16 1008.36 0.0200 12.73 13.00 0.9796
NaCN Sodium Cyanide 3 A' 148 198 0.7489 10.30 2.90 3.5523 13.26 13.32 0.9957
CS2+ Carbon disulfide cation 3 Πu 311 362 0.8569 0.66 2.07 0.3175 13.31 13.31 1.0000
OCS+ Carbonyl sulfide cation 1 Σ 2361 3118 0.7572 209.49 2764.13 0.0758 13.41 13.23 1.0133
Na2S Sodium sulfide 2 A1 9 80 0.1186 83.08 21.93 3.7878 27.29 25.03 1.0903
Na2S Sodium sulfide 1 A1 290 330 0.8788 2.73 10.33 0.2640 23.18 25.10 0.9233
SO2+ Sulfur dioxide cation 3 B2 1845 3922 0.4705 874.03 42935.23 0.0204 20.65 20.84 0.9911
Li2S dilithium sulfide 2 A1 54 136 0.4006 125.85 63.90 1.9694 8.87 8.30 1.0690
S3- Sulfur trimer anion 3 B2 519 798 0.6499 959.81 25.72 37.3121 31.97 31.97 1.0000
S3+ Sulfur trimer cation 3 B2 675 788 0.8571 222.62 0.74 299.1868 31.97 31.97 1.0000
S3+ Sulfur trimer cation 1 A1 709 809 0.8757 0.92 12.95 0.0708 31.97 31.97 1.0000
S3+ Sulfur trimer cation 2 A1 234 266 0.8804 4.24 2.23 1.9042 31.97 31.97 1.0000
SF2- sulfur difluoride anion 2 Σu 475 563 0.8432 675.27 507.48 1.3306 24.37 24.37 1.0000
NNS Nitrogen sulfide 2 Σ 586 845 0.6937 44.93 28.19 1.5938 18.99 18.87 1.0062
SNO Nitrogen oxide sulfide 3 A' 466 553 0.8433 5.48 1.98 2.7670 16.17 16.40 0.9864
SNO Nitrogen oxide sulfide 2 A' 811 932 0.8700 22.06 12.18 1.8110 18.45 18.21 1.0130
NSO sulfinyl amidogen 2 A' 745 1087 0.6854 8.81 197.10 0.0447 16.07 15.36 1.0456
NSO sulfinyl amidogen 1 A' 1145 1285 0.8911 4.93 284.17 0.0173 19.34 19.80 0.9771
CCl2- dichloromethylene anion 3 B2 332 477 0.6945 451.65 270.31 1.6709 13.99 13.98 1.0006
ClCO carbonyl monochloride 3 A' 194 380 0.5090 83.93 32.77 2.5607 18.71 18.86 0.9920
ClCO carbonyl monochloride 2 A' 576 646 0.8922 66.73 148.31 0.4499 13.25 13.25 1.0006
OClO- Chlorine dioxide anion 1 A1 699 884 0.7904 7.64 38.83 0.1968 18.85 18.43 1.0229
ClOO chloroperoxy radical 2 A' 715 1092 0.6543 18.30 33.35 0.5488 17.47 17.03 1.0259
ClOO chloroperoxy radical 1 A' 1191 1729 0.6892 24.25 139.55 0.1738 16.07 18.09 0.8884
Cl3- trichloride anion 2 Σu 48 292 0.1636 975.99 470.37 2.0749 34.97 34.97 1.0000
FClO chlorosyl fluoride 1 A' 1008 1263 0.7984 69.72 47.63 1.4639 19.23 19.50 0.9860
ClSO Sulfur chloride oxide 1 A' 1031 1593 0.6475 51.39 768.61 0.0669 18.99 19.19 0.9893
KCN Potassium cyanide 3 A' 147 202 0.7304 6.82 1.32 5.1529 13.06 13.27 0.9841
ZnCN Zinc monocyanide 1 Σ 2476 3684 0.6723 18.32 1111.03 0.0165 12.80 12.81 0.9989
AsO2 Aresenic dioxide 3 B2 1312 6549 0.2004 1064.19 1454910.00 0.0007 19.90 20.22 0.9843
SeO2+ Selenium dioxide cation 3 B2 1045 1867 0.5598 422.06 832.16 0.5072 19.56 20.11 0.9728
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
CH3 Methyl radical 2 A2" 308 403 0.7643 83.23 93.99 0.8855 1.24 1.24 1.0000
NH3- Ammonia anion 3 E 2028 2254 0.8999 6101.59 2168.70 2.8135 1.12 1.11 1.0146
NH3- Ammonia anion 3 E 2028 2254 0.8999 6101.59 2168.70 2.8135 1.12 1.11 1.0146
HCCH- acetylene anion 5 Bu 756i 2723 -0.2778 3969.78 6078.25 0.6531 1.08 1.08 1.0000
HCCH- acetylene anion 6 Bu 2916 11709 0.2490 1028.57 0.00   1.08 1.08 1.0000
HCCH- acetylene anion 4 Au 853 1354 0.6299 156.22 161.31 0.9684 1.08 1.08 1.0000
H2CN H2CN 2 A1 1639 2078 0.7889 12.22 13.28 0.9202 1.77 8.94 0.1981
H2CN H2CN 4 B1 1032 1173 0.8804 31.84 32.23 0.9878 1.35 1.36 0.9878
N2H2+ trans-diazine cation 6 Bu 672i 1768 -0.3803 2810.18 808.41 3.4762 1.07 1.07 1.0000
N2H2+ trans-diazine cation 4 Au 1027 1608 0.6390 371.17 0.00 337427.5000 1.07 1.07 1.0000
HCNH HCNH 3 A' 1704 2528 0.6742 10.87 491.22 0.0221 7.73 4.49 1.7228
H2O2+ Hydrogen peroxide cation 5 Bu 3689 5811 0.6349 1219.06 886362.90 0.0014 1.07 1.07 1.0000
H2OO water oxide 4 A' 520 777 0.6700 109.12 117.14 0.9315 12.40 5.61 2.2088
H2OO water oxide 3 A' 856 974 0.8789 261.72 96.78 2.7044 1.15 1.30 0.8806
HNO2+ nitrous acid cation 2 A' 1562 3056 0.5110 114.83 3042.18 0.0377 1.30 11.21 0.1159
HNO2+ nitrous acid cation 5 A' 445 712 0.6252 15.99 6.32 2.5304 8.84 6.22 1.4218
O3H+ protonated ozone 6 A" 452 930 0.4862 201.06 185.44 1.0842 1.16 1.31 0.8873
HNNO+ Nitrous oxide, N-protonated 5 A' 490 567 0.8628 488.35 2.53 192.8481 1.15 8.07 0.1418
HNCS Isothiocyanic acid 5 A' 340 453 0.7521 561.14 64.22 8.7371 1.12 3.04 0.3667
HNCS Isothiocyanic acid 4 A' 550 649 0.8476 72.87 458.37 0.1590 11.93 1.51 7.8867
HOClO Chlorous acid 3 A 866 1168 0.7411 92.19 85.83 1.0741 17.88 10.84 1.6490
C4+ Carbon tetramer cation 3 Σu 1337 1509 0.8860 114.49 2262.61 0.0506 12.00 12.00 1.0000
C2N2+ Cyanogen cation 4 Πg 571 641 0.8900 0.00 0.00   12.18 12.18 1.0001
BF3+ boron trifluoride cation 5 B2 2270 3942 0.5757 14698.30 161633.20 0.0909 12.52 12.50 1.0010
SSCl2 Thiothionyl chloride 1 A' 626 774 0.8095 157.21 161.09 0.9759 32.00 31.97 1.0009
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
CH4- Methane anion 4 T2 119i 983 -0.1207 4873.77 0.85 5763.6790 1.02 1.12 0.9052
CH4- Methane anion 4 T2 119i 983 -0.1207 4873.76 0.85 5763.6760 1.02 1.12 0.9052
CH4- Methane anion 4 T2 119i 983 -0.1207 4873.77 0.85 5763.6760 1.02 1.12 0.9052
CH4- Methane anion 3 T2 1696 2357 0.7196 6378.10 1487.61 4.2875 1.29 1.15 1.1207
CH4- Methane anion 3 T2 1696 2357 0.7196 6378.10 1487.61 4.2875 1.29 1.15 1.1207
CH4- Methane anion 3 T2 1696 2357 0.7196 6378.10 1487.61 4.2875 1.29 1.15 1.1207
NH4 Ammonium radical 3 T2 1855 2272 0.8165 5368.85 1482.92 3.6205 1.23 1.15 1.0616
NH4 Ammonium radical 3 T2 1855 2272 0.8165 5368.86 1482.92 3.6205 1.23 1.15 1.0616
NH4 Ammonium radical 3 T2 1855 2272 0.8165 5368.85 1482.92 3.6205 1.23 1.15 1.0616
SiH4+ Silane cation 7 B1 202i 512 -0.3949 95.33 2.50 38.1661 1.13 1.13 1.0015
SiH4+ Silane cation 6 B1 1379 1579 0.8733 434.64 211.02 2.0597 1.01 1.01 0.9998
C2H3 vinyl 4 A' 1635 1859 0.8796 1.49 2.31 0.6449 1.50 5.76 0.2612
C2H3 vinyl 9 A" 885 993 0.8914 2.47 10.54 0.2342 1.27 1.27 0.9988
CH3O+ Methoxy cation 3 A1 754 1119 0.6740 5.03 273.92 0.0184 10.61 13.37 0.7935
CH2OH Hydroxymethyl radical 9 A 412 462 0.8931 141.85 120.64 1.1758 1.08 1.08 0.9964
CH3F+ methyl fluoride cation 9 A" 472 619 0.7617 255.92 171.90 1.4888 1.45 1.42 1.0202
CH3F+ methyl fluoride cation 7 A" 2044 2380 0.8590 244.10 271.12 0.9004 1.01 1.03 0.9799
CH3Cl+ Methyl chloride cation 6 A' 454 618 0.7342 86.39 4.51 19.1583 9.15 7.05 1.2974
CuCH3 monomethyl copper 3 A1 573 724 0.7909 44.88 38.76 1.1579 4.10 3.51 1.1685
Be(OH)2 Beryllium hydroxide 5 A 202 247 0.8204 155.97 123.82 1.2596 1.08 1.08 0.9993
H2COO Dioxymethyl radical 6 A' 524 1103 0.4753 35.33 572.58 0.0617 11.19 3.99 2.8029
H2COO Dioxymethyl radical 7 A' 454 560 0.8110 12.33 7.15 1.7235 3.44 2.96 1.1635
Mg(OH)2 Magnesium dihydroxide 3 A 218 367 0.5940 108.99 51.38 2.1210 1.39 1.45 0.9628
Mg(OH)2 Magnesium dihydroxide 8 B 217 365 0.5942 369.12 300.35 1.2289 1.76 1.29 1.3591
Mg(OH)2 Magnesium dihydroxide 5 A 74 118 0.6214 212.00 149.23 1.4206 1.08 1.09 0.9843
HCCCN+ Cyanoacetylene cation 2 Σ 2011 3287 0.6118 100.07 36.56 2.7376 7.49 1.23 6.0933
HCCCN+ Cyanoacetylene cation 3 Σ 1716 2480 0.6919 428.74 718.23 0.5969 11.71 6.19 1.8913
HCCCN+ Cyanoacetylene cation 6 Π 489 645 0.7580 3.81 0.12 30.8695 7.78 11.81 0.6590
HCCCN+ Cyanoacetylene cation 1 Σ 3510 4252 0.8256 201.13 4145.41 0.0485 1.13 7.74 0.1461
HCCCN+ Cyanoacetylene cation 7 Π 224 258 0.8657 0.02 0.49 0.0330 5.33 5.43 0.9819
HCCCN+ Cyanoacetylene cation 7 Π 223 254 0.8773 0.22 0.43 0.5136 6.18 4.65 1.3284
HSO3 HOSO2 4 A 915 1143 0.8010 241.57 62.86 3.8429 16.58 11.98 1.3840
HSO3 HOSO2 8 A 363 413 0.8775 15.04 16.04 0.9379 4.67 13.89 0.3360
C3O2 Carbon suboxide 7 Πu 86 106 0.8099 0.57 0.01 40.8273 13.28 13.29 0.9988
C3O2 Carbon suboxide 7 Πu 86 106 0.8099 0.57 0.01 40.8273 13.28 13.29 0.9988
C3O2+ Carbon suboxide cation 3 Σu 2093 2974 0.7038 1327.09 7600.40 0.1746 12.96 12.97 0.9993
C3O2+ Carbon suboxide cation 1 Σg 2305 2965 0.7775 0.00 0.00   13.05 13.07 0.9982
N2O3 Dinitrogen trioxide 9 A" 116 175 0.6612 1.66 0.14 11.5523 14.93 15.09 0.9892
F3NO Nitrogen trifluoride oxide 1 A1 1665 1911 0.8709 682.50 516.21 1.3221 14.74 14.77 0.9979
CCl4+ Carbon tetrachloride cation 7 B1 658i 324 -2.0300 2311.64 28.25 81.8396 20.80 30.68 0.6779
CCl4+ Carbon tetrachloride cation 6 B1 834 3814 0.2187 2.26 0.00   13.73 13.35 1.0291
CCl4+ Carbon tetrachloride cation 4 A1 197 241 0.8182 22.37 0.87 25.6827 34.09 34.77 0.9804
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
SiH5+ Silane, protonated 12 A" 45 61 0.7355 0.10 0.04 2.4485 1.01 1.01 0.9997
SiH5+ Silane, protonated 8 A' 572 683 0.8368 191.57 31.09 6.1621 1.12 1.06 1.0534
N2H4+ hydrazine cation 4 Ag 294 445 0.6594 0.00 0.00   1.41 1.41 1.0042
CH3OH- Methyl alcohol anion 7 A' 489 662 0.7384 356.34 107.07 3.3281 1.07 1.06 1.0130
CH3OH+ Methyl alcohol cation 12 A 68 229 0.2966 144.20 231.03 0.6241 1.12 1.07 1.0436
H2OH2O water dimer 7 A' 182 214 0.8482 116.84 171.24 0.6823 3.49 3.13 1.1160
H2OH2O water dimer 6 A' 383 437 0.8773 94.95 40.27 2.3578 1.10 1.08 1.0195
H2OH2O water dimer 11 A" 142 159 0.8887 157.19 186.08 0.8447 1.07 1.07 0.9968
Si2H4 Disilene 4 Ag 144 338 0.4251 0.00 0.00   1.25 1.32 0.9438
NH4Cl Ammonium chloride 7 E 700 824 0.8490 110.90 100.23 1.1065 1.05 1.05 0.9978
NH4Cl Ammonium chloride 7 E 700 824 0.8490 110.90 100.23 1.1065 1.05 1.05 0.9978
NH4Cl Ammonium chloride 4 A1 184 210 0.8779 9.77 23.59 0.4140 5.38 5.15 1.0446
CH3ClH+ methyl chloride, protonated 8 A' 479 610 0.7848 131.08 59.61 2.1989 8.44 8.06 1.0467
CH3ClH+ methyl chloride, protonated 12 A" 201 227 0.8859 61.10 62.95 0.9706 1.03 1.03 1.0008
C3H3 Propargyl radical 7 B1 440 594 0.7419 60.23 94.53 0.6372 1.14 1.46 0.7785
C3H3 Propargyl radical 3 A1 1931 2403 0.8035 18.58 8.17 2.2740 7.33 5.23 1.4020
C3H3 Propargyl radical 12 B2 367 410 0.8957 5.19 5.64 0.9204 2.89 2.58 1.1186
C3H3 cyclopropenyl radical 9 A" 1146 3130 0.3660 15.86 2558.55 0.0062 1.35 1.07 1.2617
C3H3 cyclopropenyl radical 8 A" 3449 6993 0.4932 9.04 412562.90 0.0000 1.08 4.67 0.2311
C3H3 cyclopropenyl radical 12 A" 529 855 0.6188 131.69 0.18 736.5469 2.97 1.46 2.0366
CH3CN+ Acetonitrile cation 3 A' 2213 2929 0.7557 80.86 164.58 0.4913 12.22 1.12 10.9358
HCNCH2+ 2H-Azirine cation 8 A' 428 570 0.7506 20.50 18.26 1.1229 8.04 2.47 3.2598
HCNCH2+ 2H-Azirine cation 3 A' 2091 2733 0.7650 8.45 1427.97 0.0059 5.61 2.35 2.3862
HCNCH2+ 2H-Azirine cation 7 A' 738 836 0.8828 37.33 41.73 0.8946 3.30 1.82 1.8117
H2CNCH methyleneaminomethylene 12 A" 303 382 0.7932 6.28 4.05 1.5502 3.73 3.08 1.2135
CH2CHO Vinyloxy radical 4 A' 1614 1935 0.8342 10.39 305.54 0.0340 1.28 10.21 0.1252
BH3CO Borane carbonyl 4 A1 540 708 0.7622 3.76 35.49 0.1058 5.99 4.70 1.2754
HNCCNH Ethenediimine 5 Ag 320 360 0.8895 0.00 0.00   6.40 6.72 0.9518
N2O4 Dinitrogen tetroxide 4 Au 65 105 0.6225 0.00 0.00   15.99 15.99 1.0000
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
CH3BH2 methylborane 15 A" 113 134 0.8458 0.75 1.54 0.4851 1.01 1.01 0.9992
CH3NH2+ methyl amine cation 15 A" 66 94 0.7062 0.59 2.78 0.2118 1.01 1.01 0.9983
H2ONH3 Water Ammonia Dimer 9 A' 185 210 0.8823 19.89 14.53 1.3691 2.62 3.25 0.8057
H5O2+ Dihydroxonium ion 15 B 703i 356 -1.9729       1.02 1.07 0.9554
H5O2+ Dihydroxonium ion 13 B 596 886 0.6731       1.20 1.08 1.1165
SiH3NH2 Silane, amino 15 A" 173 195 0.8895 12.59 15.31 0.8224 1.01 1.02 0.9967
CH3CHN methylmethaniminyl radical 4 A' 1676 2121 0.7900 7.88 65.11 0.1211 2.47 10.52 0.2349
CH3CHN methylmethaniminyl radical 15 A" 179 201 0.8900 2.15 2.07 1.0403 1.25 1.26 0.9967
H2OH2CO water formaldehyde dimer 15 A 116 152 0.7608 46.36 33.10 1.4008 3.35 3.62 0.9273
H2OH2CO water formaldehyde dimer 14 A 132 167 0.7886 123.06 114.02 1.0793 1.07 1.08 0.9903
H2OH2CO water formaldehyde dimer 12 A 191 228 0.8368 27.62 41.21 0.6701 1.10 1.08 1.0131
H2OH2CO water formaldehyde dimer 13 A 174 197 0.8829 32.01 35.20 0.9094 4.12 4.38 0.9411
H2OH2CO water formaldehyde dimer 10 A 524 589 0.8889 246.88 247.85 0.9961 1.06 1.05 1.0095
C3H3N+ acrylonitrile cation 4 A' 2072 2632 0.7872 445.82 1645.56 0.2709 11.93 12.49 0.9554
CH3N3 methyl azide 15 A" 114 149 0.7669 1.39 0.92 1.5087 1.18 1.20 0.9814
CH3NO2 Methane, nitro- 15 A" 20 28 0.6981 0.02 0.05 0.4491 1.10 1.09 1.0019
NH2COOH Carbamic acid 15 A 225 387 0.5827 334.77 326.77 1.0245 1.22 1.23 0.9972
N2O5 Dinitrogen pentoxide 15 A" 27 39 0.6839 0.67 0.00 2228.0000 15.95 15.96 0.9998
PF6 Hexafluorophosphate neutral 12 B2 2936 12841 0.2287 119102.10 0.00   23.93 23.46 1.0201
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
NH3NH3 Ammonia Dimer 18 Bu 55 103 0.5371 285.18 321.79 0.8862 1.04 1.04 0.9982
NH3NH3 Ammonia Dimer 13 Bg 110 141 0.7748 0.00 0.00   1.09 1.10 0.9935
NH3NH3 Ammonia Dimer 10 Au 86 105 0.8188 28.71 31.93 0.8992 1.01 1.02 0.9990
NH3NH3 Ammonia Dimer 6 Ag 127 154 0.8256 0.00 0.00   4.59 4.74 0.9679
NH3NH3 Ammonia Dimer 9 Au 235 263 0.8940 139.14 132.33 1.0515 1.04 1.04 0.9997
NH3NH3 Ammonia Dimer 5 Ag 443 494 0.8962 0.00 0.00   1.09 1.10 0.9935
BH3NH3 borane ammonia 5 A1 604 673 0.8978 34.66 14.29 2.4262 4.97 4.72 1.0523
CH3NH3 methyl ammonium radical 12 E 1781i 871 -2.0444 20713.01 18.60 1113.8070 1.06 1.06 0.9958
CH3NH3 methyl ammonium radical 12 E 1781i 871 -2.0444 20713.01 18.60 1113.8060 1.06 1.06 0.9958
CH3NH3 methyl ammonium radical 8 E 1638 2211 0.7409 9.11 1248.05 0.0073 1.05 1.15 0.9106
CH3NH3 methyl ammonium radical 8 E 1638 2211 0.7409 9.11 1248.05 0.0073 1.05 1.15 0.9106
CH3NH3 methyl ammonium radical 11 E 960 1070 0.8970 10.54 181.17 0.0582 1.06 1.16 0.9181
CH3NH3 methyl ammonium radical 11 E 960 1070 0.8970 10.54 181.17 0.0582 1.06 1.16 0.9181
BH3PH3 borane phosphine 5 A1 423 539 0.7853 9.28 0.40 23.0253 5.26 4.74 1.1112
BH3PH3 borane phosphine 6 A2 224 259 0.8636 0.00 0.00   1.01 1.01 1.0000
CH3CHCH 1-propenyl radical 18 A" 184 218 0.8438 0.02 0.01 3.0441 1.25 1.25 0.9987
CH3CHCH 1-propenyl radical 5 A' 1659 1919 0.8647 2.76 3.55 0.7766 1.48 6.84 0.2159
CH3CHOH+ acetaldehyde, protonated 18 A" 116 136 0.8516 0.42 0.14 3.0660 1.22 1.22 1.0002
HCOOHH2O Formic acid water dimer 15 A 247 303 0.8142 77.83 80.76 0.9637 1.20 1.14 1.0586
HCOOHH2O Formic acid water dimer 18 A 166 197 0.8431 7.98 7.88 1.0129 4.26 2.24 1.9023
HCOOHH2O Formic acid water dimer 16 A 218 250 0.8711 29.89 41.29 0.7240 6.55 6.41 1.0217
HCOOHH2O Formic acid water dimer 13 A 578 654 0.8841 244.33 173.89 1.4051 1.12 1.46 0.7699
HCOOHH2O Formic acid water dimer 17 A 179 202 0.8849 52.74 26.46 1.9933 1.67 3.29 0.5092
H2OHCOOH Water formic acid dimer 1 15 A 134 174 0.7704 92.56 96.13 0.9628 1.12 1.05 1.0762
H2OHCOOH Water formic acid dimer 1 17 A 88 109 0.8083 32.30 15.30 2.1111 5.37 6.92 0.7750
H2OHCOOH Water formic acid dimer 1 16 A 119 146 0.8123 6.91 0.42 16.4551 5.40 6.96 0.7754
H2OHCOOH Water formic acid dimer 1 13 A 378 457 0.8277 234.86 261.56 0.8979 1.08 1.05 1.0219
H2OHCOOH Water formic acid dimer 1 18 A 64 77 0.8341 9.61 12.58 0.7637 2.03 2.02 1.0063
H2OHCOOH Water formic acid dimer 2 17 A 88 112 0.7890 16.87 15.16 1.1131 5.50 6.56 0.8385
H2OHCOOH Water formic acid dimer 2 15 A 162 203 0.8007 85.72 116.29 0.7371 1.57 1.12 1.3941
H2OHCOOH Water formic acid dimer 2 18 A 82 100 0.8146 15.96 14.46 1.1034 1.94 1.83 1.0604
H2OHCOOH Water formic acid dimer 2 16 A 155 176 0.8848 37.57 0.97 38.7448 2.39 7.07 0.3384
CHOCH2OH hydroxy acetaldehyde 17 A" 348 392 0.8895 117.67 98.85 1.1904 1.18 1.14 1.0338
NH2CSNH2 Thiourea 9 A 234 391 0.6000 88.47 157.77 0.5607 1.15 1.13 1.0196
NH2CSNH2 Thiourea 18 B 363 414 0.8766 549.21 1.95 282.1116 1.19 3.82 0.3111
SiCl3CH3 methyltrichlorosilane 6 A2 176 198 0.8879 0.00 0.00   1.02 1.02 0.9999
C2H2N4 sym-tetrazine 13 B2u 886 1079 0.8212 99.92 29.56 3.3806 13.25 3.62 3.6602
C2H2O4 Oxalic Acid 10 Au 9i 128 -0.0689 4.57 5.19 0.8815 11.98 10.88 1.1004
S4N4 Tetrasulfur tetranitride 11 E 825 2139 0.3854 98.67 18739.56 0.0053 18.13 16.34 1.1101
S4N4 Tetrasulfur tetranitride 11 E 825 2139 0.3854 98.67 18739.56 0.0053 18.13 16.34 1.1101
S4N4 Tetrasulfur tetranitride 14 E 355 433 0.8212 84.34 0.51 165.6931 16.51 25.36 0.6512
S4N4 Tetrasulfur tetranitride 14 E 355 433 0.8212 84.34 0.51 165.6927 16.51 25.36 0.6512
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C2H7+ Ethane, protonated 11 A 199 254 0.7809 0.36 1.72 0.2080 1.03 1.04 0.9906
C2H7+ Ethane, protonated 10 A 286 356 0.8046 4.02 4.85 0.8292 3.39 4.49 0.7556
C2H7+ Ethane, protonated 4 A 1872 2111 0.8865 8.93 45.80 0.1951 1.10 1.10 1.0040
H2OCH3OH water methanol dimer 21 A 31 73 0.4309 2.24 40.27 0.0557 1.87 1.09 1.7185
H2OCH3OH water methanol dimer 20 A 46 96 0.4762 30.40 17.27 1.7606 1.46 2.02 0.7213
H2OCH3OH water methanol dimer 16 A 397 497 0.8001 96.53 23.75 4.0646 1.11 1.08 1.0261
H2OCH3OH water methanol dimer 18 A 175 202 0.8674 2.63 4.97 0.5293 5.36 4.23 1.2677
H2OCH3OH water methanol dimer 19 A 117 132 0.8856 141.48 131.91 1.0725 1.10 1.36 0.8098
CH3OHH2O methanol water dimer 11 A' 267 311 0.8612 282.69 281.77 1.0033 1.41 1.35 1.0474
CH3OHH2O methanol water dimer 12 A' 162 187 0.8687 13.96 6.65 2.1004 3.63 3.88 0.9354
CH3OHH2O methanol water dimer 20 A" 90 103 0.8730 10.55 35.08 0.3007 1.02 1.03 0.9882
CH3CONH2 Acetamide 20 A 229 326 0.7014 306.40 268.49 1.1412 1.23 1.24 0.9885
CH3COCH2 Acetonyl radical 21 A" 66 103 0.6445 0.06 0.00 31.9444 1.07 1.07 0.9958
CH3COCH2 Acetonyl radical 5 A' 1627 2105 0.7732 35.82 775.10 0.0462 1.85 11.99 0.1546
C3H5Cl 1-Propene, 3-chloro- 19 A 435 531 0.8182 1.24 2.22 0.5590 2.31 3.17 0.7289
C3H5Cl 1-Propene, 3-chloro- 21 A 113 136 0.8320 0.54 1.84 0.2934 2.93 1.72 1.7065
C4H4N pyrrolide radical 21 B2 977i 899 -1.0868 802.90 7.00 114.7158 10.78 4.46 2.4183
C4H4N pyrrolide radical 15 B2 3423 58753 0.0583 25.25 0.00   1.09 12.19 0.0895
C4H4N pyrrolide radical 17 B2 1465 3272 0.4478 68.88 77.77 0.8858 1.73 1.09 1.5937
C4H4N pyrrolide radical 19 B2 1117 1327 0.8422 0.68 43.04 0.0157 2.84 1.22 2.3357
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
CH3CHCH3+ Isopropyl cation 12 A 163 186 0.8799 4.75 9.65 0.4922 1.06 1.07 0.9904
C3H7+ cyclopropane, protonated 14 A' 245 411 0.5971 94.73 50.44 1.8779 5.48 5.06 1.0822
C3H7+ cyclopropane, protonated 24 A" 106 135 0.7830 1.53 4.59 0.3340 1.08 1.09 0.9958
CH3COCH3 Acetone 12 A 51 62 0.8171 0.00 0.00   1.02 1.02 0.9994
C3H6S Thietane 14 A' 129 191 0.6724 1.78 1.74 1.0254 1.77 1.77 0.9968
CH3CSCH3 Thioacetone 12 A2 80 105 0.7577 0.00 0.00   1.02 1.02 0.9984
CH2ClCH2OH2+ 2-chloroethanol, protonated 12 A' 617 721 0.8553 395.76 452.59 0.8744 1.30 1.56 0.8317
CH2CHCONH2 Acrylamide 23 A 180 286 0.6301 254.08 6.65 38.1999 1.51 3.21 0.4695
C6H4 Benzyne 24 B2 316 591 0.5343 189.90 10.10 18.8092 10.75 9.54 1.1268
C4H4N2 Pyrazine 17 B2u 1203 1364 0.8818 0.90 0.13 6.8195 2.19 7.67 0.2848
C2H4CO3 Ethylene carbonate 12 A 74 204 0.3611 0.48 0.88 0.5477 2.18 2.16 1.0088
C2H4CO3 Ethylene carbonate 24 B 140 188 0.7424 1.69 2.24 0.7531 5.07 5.06 1.0024
C2H4N2S2 Ethanedithioamide 13 Au 11i 14 -0.8270 16.00 6.09 2.6269 7.62 8.87 0.8590
C6N4- tetracyanoethylene anion 9 B1u 2449 3296 0.7429 0.57 71260.12 0.0000 12.68 12.79 0.9914
C6N4- tetracyanoethylene anion 15 B2u 2380 3104 0.7668 246.27 4226.51 0.0583 12.71 12.74 0.9973
C6N4- tetracyanoethylene anion 19 B3g 2372 3071 0.7726 0.00 0.00   12.72 12.75 0.9979
C6N4- tetracyanoethylene anion 1 Ag 2459 3042 0.8083 0.00 0.00   12.68 12.75 0.9945
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
CH3CHCHCH2 methylallyl radical 27 A" 137 154 0.8905 0.38 0.70 0.5527 1.19 1.20 0.9898
C4H6O Furan, 2,3-dihydro- 27 A 66 164 0.4035 2.74 2.10 1.3079 1.99 1.98 1.0069
C4H6S Thiophene, 2,3-dihydro- 27 A 158 189 0.8374 1.44 1.35 1.0683 1.99 2.00 0.9971
C6H5 phenyl 13 A2 404 469 0.8610 0.00 0.00   2.87 3.00 0.9593
C6H5 phenyl 12 A2 850 975 0.8718 0.00 0.00   1.25 1.25 1.0046
C6H5 phenyl 21 B2 1666 1891 0.8808 0.79 7.94 0.0992 3.69 8.44 0.4376
C6H5 phenyl 18 B1 436 493 0.8839 2.46 5.43 0.4536 3.58 3.74 0.9552
C6H5 phenyl 4 A1 1639 1836 0.8927 0.69 2.38 0.2879 2.88 7.50 0.3844
C6H5 phenyl 15 B1 920 1024 0.8985 0.75 0.74 1.0088 1.32 1.28 1.0339
C3H5Cl3 Propane, 1,2,3-trichloro- 27 A" 17 30 0.5847 1.76 1.18 1.4885 2.70 2.68 1.0062
Fe(CO)5 Iron pentacarbonyl 5 A1 262 595 0.4406 42.05 146.56 0.2869 14.11 14.24 0.9907
Fe(CO)5 Iron pentacarbonyl 4 A1 370 631 0.5854 31.94 81.33 0.3928 16.09 16.63 0.9676
Fe(CO)5 Iron pentacarbonyl 7 A2 287 488 0.5884 0.00 0.00   12.74 12.67 1.0062
Fe(CO)5 Iron pentacarbonyl 11 B2 394 659 0.5975 0.00 0.00   13.13 14.29 0.9187
Fe(CO)5 Iron pentacarbonyl 3 A1 493 786 0.6272 119.10 98.82 1.2052 15.89 15.54 1.0231
Fe(CO)5 Iron pentacarbonyl 17 E 373 588 0.6332 193.54 3.89 49.7852 17.32 13.71 1.2634
Fe(CO)5 Iron pentacarbonyl 17 E 373 588 0.6332 193.54 3.89 49.7857 17.32 13.71 1.2634
Fe(CO)5 Iron pentacarbonyl 12 B2 198 310 0.6399 0.00 0.00   13.54 14.27 0.9486
Fe(CO)5 Iron pentacarbonyl 15 E 535 806 0.6635 13.70 866.80 0.0158 15.51 17.14 0.9049
Fe(CO)5 Iron pentacarbonyl 15 E 535 806 0.6635 13.70 866.80 0.0158 15.51 17.14 0.9049
Fe(CO)5 Iron pentacarbonyl 18 E 318 428 0.7417 1.07 0.30 3.5604 12.72 12.75 0.9981
Fe(CO)5 Iron pentacarbonyl 18 E 318 428 0.7417 1.07 0.30 3.5590 12.72 12.75 0.9981
Fe(CO)5 Iron pentacarbonyl 16 E 476 616 0.7724 78.15 60.27 1.2966 12.42 14.12 0.8801
Fe(CO)5 Iron pentacarbonyl 16 E 476 616 0.7724 78.15 60.27 1.2966 12.42 14.12 0.8801
Fe(CO)5 Iron pentacarbonyl 8 B1 518 651 0.7955 0.00 0.00   12.21 12.27 0.9951
Fe(CO)5 Iron pentacarbonyl 19 E 100 122 0.8220 7.71 16.78 0.4593 17.40 16.76 1.0380
Fe(CO)5 Iron pentacarbonyl 19 E 100 122 0.8220 7.71 16.78 0.4593 17.40 16.76 1.0380
Fe(CO)5 Iron pentacarbonyl 9 B1 98 110 0.8893 0.00 0.00   15.63 15.53 1.0063
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
H2OCH3OCH3 water dimethylether dimer 29 A 55 89 0.6161 9.69 11.40 0.8498 2.83 2.99 0.9454
H2OCH3OCH3 water dimethylether dimer 28 A 137 162 0.8433 99.81 107.97 0.9244 1.26 1.14 1.1041
H2OCH3OCH3 water dimethylether dimer 27 A 145 171 0.8461 30.94 18.41 1.6806 2.91 3.31 0.8775
H2OCH3OCH3 water dimethylether dimer 24 A 290 326 0.8905 80.87 89.93 0.8992 1.21 1.14 1.0681
H2OCH3OCH3 water dimethylether dimer 22 A 582 652 0.8926 177.07 183.31 0.9659 1.04 1.04 1.0028
C3H7NO Propanamide 27 A 276 327 0.8424 10.36 264.79 0.0391 3.30 1.25 2.6362
C3H7NO Propanamide 28 A 235 265 0.8874 44.00 9.20 4.7839 1.09 3.30 0.3298
C5H6O 2H-Pyran 30 A 169 223 0.7607 3.55 2.57 1.3814 2.28 2.14 1.0697
C2H6N2O2 Dimethylnitroamine 29 A 143 170 0.8460 5.09 3.85 1.3230 1.34 1.18 1.1369
CH6N4S Carbonothioic dihydrazide 30 A 55 87 0.6340 13.04 38.55 0.3382 3.89 3.09 1.2574
C4H6OS 4,5-dihydrothiophene-3-ol 29 A 216 243 0.8881 146.66 42.40 3.4587 1.14 2.93 0.3889
C4H6OS 4,5-dihydrothiophene-3-ol 30 A 159 179 0.8918 9.14 8.58 1.0652 1.96 2.15 0.9095
C4H6OS 4,5-dihydrothiophene-2-ol 30 A 156 177 0.8803 1.77 2.91 0.6101 2.39 2.76 0.8675
C4H6OS 2,3-dihydrothiophene-2-ol 30 A 77 146 0.5284 2.09 1.57 1.3372 2.97 3.34 0.8891
C5H5NO 3-Pyridinol 29 A" 300 355 0.8448 147.52 141.69 1.0411 1.22 1.11 1.1030
C5H5NO 2(3H)-Pyridinone 30 A 38 95 0.3997 2.58 2.01 1.2827 3.36 4.29 0.7839
C6H4F2 1,4-difluorobenzene 20 B2u 1276 1449 0.8805 0.66 0.25 2.6382 3.69 6.00 0.6158
C6H4Cl2 1,4-dichlorobenzene 20 B2u 1260 1424 0.8850 2.80 4.39 0.6370 2.91 3.96 0.7354
C6F6 hexafluorobenzene 9 B2u 1206 1448 0.8331 0.00 0.00   12.00 12.00 1.0003
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C(CH3)3 Tert-butyl radical 11 A2 142 163 0.8737 0.00 0.00   1.01 1.01 1.0001
C5H8 Cyclopentene 18 A' 150 183 0.8201 0.11 0.16 0.6904 1.60 1.60 1.0021
C5H8 2,3-Pentadiene 17 A 151 1354 0.1116 1.18 16.47 0.0714 2.08 1.22 1.7068
C5H8 2,3-Pentadiene 16 A 180 1462 0.1233 0.12 4.71 0.0255 1.19 1.25 0.9574
C5H8 2,3-Pentadiene 15 A 322 1463 0.2199 0.99 2.27 0.4376 2.64 1.22 2.1656
C5H8 2,3-Pentadiene 14 A 594 1489 0.3990 4.72 0.00 1150.4880 3.96 2.28 1.7360
C5H8 2,3-Pentadiene 8 A 1559 3099 0.5031 0.57 50.31 0.0113 1.23 1.04 1.1876
C5H8 2,3-Pentadiene 6 A 1629 3174 0.5132 4.12 18.63 0.2210 1.05 1.10 0.9484
C5H8 2,3-Pentadiene 7 A 1595 3099 0.5146 0.00 7.26 0.0003 1.84 1.04 1.7773
C5H8 2,3-Pentadiene 5 A 1657 3174 0.5219 2.37 18.82 0.1261 1.28 1.10 1.1605
C5H8 2,3-Pentadiene 13 A 889 1546 0.5751 0.01 5.63 0.0018 2.26 1.05 2.1594
C5H8 2,3-Pentadiene 9 A 1256 2078 0.6044 0.15 3.10 0.0480 1.51 10.53 0.1430
C5H8 2,3-Pentadiene 12 A 1002 1547 0.6479 21.02 5.21 4.0354 1.11 1.05 1.0575
C5H8 2,3-Pentadiene 11 A 1173 1558 0.7530 1.34 6.57 0.2041 1.47 1.04 1.4088
C5H8 2,3-Pentadiene 10 A 1198 1568 0.7642 2.45 2.56 0.9546 1.76 1.14 1.5429
C5H8 Cyclobutane, methylene- 19 A' 99 120 0.8224 0.02 0.13 0.1233 1.87 2.02 0.9274
C2H3OC2H5 Ethene, ethoxy- 33 A 51 69 0.7388 1.37 1.54 0.8917 2.10 2.13 0.9858
CH2C(CH3)OCH3 1-Propene, 2-methoxy- 33 A 66 83 0.7867 7.48 7.67 0.9757 2.53 2.81 0.8984
C4H8O Cyclobutanol 20 A' 190 212 0.8958 1.98 2.27 0.8747 1.99 2.07 0.9629
C5H7N 1H-Pyrrole, 1-methyl- 33 A 87 103 0.8380 0.15 0.05 2.8616 1.05 1.05 1.0006
HCONH2CN2H4 formamide aminomethanimine dimer 28 A 197 229 0.8581 56.16 65.17 0.8618 3.81 3.83 0.9956
C3H7ONO Propyl nitrite 33 A 42 62 0.6725 0.57 0.05 11.6283 6.59 5.59 1.1807
C3H7ONO Propyl nitrite 30 A 211 260 0.8098 0.62 1.21 0.5151 5.62 1.56 3.6019
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
B4H10 Tetraborane(10) 36 B2 247 392 0.6312 0.00 2.71 0.0003 2.34 1.05 2.2352
B4H10 Tetraborane(10) 35 B2 422 558 0.7571 11.37 11.54 0.9853 1.12 3.38 0.3315
B4H10 Tetraborane(10) 11 A1 536 610 0.8791 0.01 0.12 0.1200 3.93 4.26 0.9222
C4H9N Cyclobutylamine 21 A' 165 206 0.8040 1.57 2.09 0.7483 1.99 2.05 0.9685
C5H8O Cyclopentanone 18 A 246 1287 0.1914 0.04 3.44 0.0107 1.59 1.47 1.0859
C5H8O Cyclopentanone 17 A 610 1339 0.4560 5.66 8.83 0.6404 3.40 1.39 2.4379
C5H8O Cyclopentanone 8 A 1486 3102 0.4791 0.51 5.60 0.0906 1.41 1.07 1.3259
C5H8O Cyclopentanone 7 A 1602 3102 0.5162 0.08 4.82 0.0157 1.09 1.07 1.0212
C5H8O Cyclopentanone 6 A 1659 3112 0.5331 0.46 19.51 0.0237 1.11 1.07 1.0419
C5H8O Cyclopentanone 16 A 774 1347 0.5748 0.23 2.41 0.0952 1.96 1.44 1.3624
C5H8O Cyclopentanone 15 A 884 1382 0.6401 0.40 2.09 0.1911 2.44 1.55 1.5750
C5H8O Cyclopentanone 5 A 2041 3115 0.6554 301.60 27.33 11.0369 12.27 1.06 11.5670
C5H8O Cyclopentanone 14 A 958 1387 0.6903 0.21 0.24 0.9069 2.63 1.35 1.9511
C5H8O Cyclopentanone 13 A 1060 1515 0.6997 0.05 0.05 0.8491 1.24 1.08 1.1448
C5H8O Cyclopentanone 12 A 1108 1516 0.7310 0.36 19.10 0.0189 1.80 1.09 1.6571
C5H8O Cyclopentanone 9 A 1450 1812 0.8003 0.00 138.09 0.0000 1.39 12.47 0.1111
C5H8O Cyclopentanone 11 A 1298 1557 0.8336 1.77 5.68 0.3115 1.39 1.09 1.2764
C5H8O Cyclopentanone 10 A 1341 1570 0.8540 0.33 1.25 0.2650 1.46 1.11 1.3219
C4H8O2 1,3-Dioxolane, 2-methyl- 35 A 215 240 0.8942 3.77 2.16 1.7435 1.96 1.39 1.4132
N(CH3)2CONH2 Urea, N,N-dimethyl- 36 A 44 62 0.7095 3.70 1.59 2.3307 1.30 1.84 0.7046
N(CH3)2CONH2 Urea, N,N-dimethyl- 35 A 106 136 0.7797 6.56 6.35 1.0328 2.15 2.37 0.9038
C5H8O Furan, 2,3-dihydro-5-methyl- 36 A 75 161 0.4638 2.59 1.27 2.0373 1.97 1.50 1.3171
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C4H9NO Butanamide 35 A 261 316 0.8252 0.61 259.95 0.0024 1.08 1.25 0.8582
C6H5CH3 toluene 39 A" 16 57 0.2888 0.17 0.20 0.8122 1.04 1.04 1.0002
C5H8O2 Acetylacetone 20 A 48 61 0.7854 9.40 6.92 1.3587 4.65 4.85 0.9588
C5H8O2 Acetylacetone 39 B 56 69 0.7992 13.69 11.51 1.1899 3.86 3.99 0.9669
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C5H11 2-Methylbut-2-yl radical 42 A 50 69 0.7197 0.04 0.07 0.5548 1.83 1.89 0.9683
C6H10 Cyclopentene, 1-methyl- 42 A 142 165 0.8651 0.06 0.13 0.4428 1.66 1.72 0.9634
C6H10 Cyclopentene, 4-methyl- 42 A 117 131 0.8981 0.04 0.03 1.1070 2.20 2.18 1.0117
C5H10O 2-Pentanone 42 A" 28 33 0.8522 0.30 0.32 0.9534 1.44 1.46 0.9869
C5H10O Oxetane, 3,3-dimethyl- 24 A' 51 139 0.3654 7.14 6.88 1.0366 3.20 3.25 0.9870
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C5H9NO2 Proline 44 A 43 56 0.7813 0.19 0.17 1.0702 2.56 2.54 1.0072
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C6H12 (E)-3-methylpent-2-ene 48 A 59 71 0.8244 0.01 0.04 0.3261 1.85 2.11 0.8729
C6H12 3-methylenepentane 24 A 34 63 0.5327 0.01 0.01 0.3704 2.29 2.37 0.9671
C6H12 (1r,3r)-1,3-dimethylcyclobutane 28 A' 103 129 0.7986 0.01 0.02 0.2650 2.44 2.46 0.9911
C6H12 Ethylcyclobutane 47 A 138 173 0.8022 0.00 0.02 0.2096 1.71 1.72 0.9964
C4H6(CH3)2 1,1-dimethylcyclobutane 28 A' 148 189 0.7842 0.00 0.01 0.1791 1.91 1.94 0.9815
C5H12S 1-Butanethiol, 2-methyl- 48 A 57 65 0.8642 8.03 6.74 1.1909 2.28 2.27 1.0046
C5H12S 2-Butanethiol, 3-methyl- 48 A 61 68 0.8979 2.26 1.88 1.2053 2.77 2.71 1.0200
C10H8 Azulene 48 B2 603i 333 -1.8075 24.30 0.92 26.3542 9.14 4.43 2.0599
C10H8 Azulene 47 B2 362 503 0.7199 0.76 1.94 0.3899 4.41 5.62 0.7853
C10H8 Azulene 46 B2 567 784 0.7230 0.00 0.09 0.0000 5.43 5.48 0.9909
C10H8 Azulene 45 B2 912 1083 0.8423 5.63 0.26 21.3502 4.51 1.70 2.6507
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C8H14 Bicyclo[2.2.2]octane 11 A1 26 125 0.2096 0.00 0.00   1.73 1.75 0.9922
Formula Name Mode Number Symmetry Frequency (cm-1) IR Intensity (km mol-1) Reduced mass
HF MP2 ratio HF MP2 ratio HF MP2 ratio
C14H14 Bibenzyl 39 A 49 55 0.8856 0.01 0.00 1.9167 4.43 4.11 1.0773