IAU list of important spectral lines

Radio frequencies of the most important astrophysical spectral lines

1. IAU list of important spectral lines

At the XXIst General Assembly of the International Astronomical Union, IAU, (Buenos Aires, July 23 – August 1, 1991) the astrophysically most important spectral lines have been carefully reviewed. The IAU listed the revision of these spectral lines as reproduced below. The IAU expressed the need to protect these frequency bands from in-band, band-edge and harmonic emissions, especially from space-borne transmitters.

Substance Rest Frequency Suggested Minimum Bandwidth Notes
Deuterium (DI) 327.384 MHz 327.0 – 327.7 MHz  
Hydrogen (HI) 1420.406 MHz 1370.0 – 1427.0 MHz (2),(3)
Hydroxyl radical (OH) 1612.231 MHz 1606.8 – 1613.8 MHz (3),(4)
Hydroxyl radical (OH) 1665.402 MHz 1659.8 – 1667.1 MHz (4)
Hydroxyl radical (OH) 1667.359 MHz 1661.8 – 1669.0 MHz (4)
Hydroxyl radical (OH) 1720.530 MHz 1714.8 – 1722.2 MHz (3),(4)
Methyladyne (CH) 3263.794 MHz 3252.9 – 3267.1 MHz (3),(4)
Methyladyne (CH) 3335.481 MHz 3324.4 – 3338.8 MHz (3),(4)
Methyladyne (CH) 3349.193 MHz 3338.0 – 3352.5 MHz (3),(4)
Formaldehyde (H₂CO) 4829.660 MHz 4813.6 – 4834.5 MHz (3),(4)
Methanol (CH₂OH) 6668.518 MHz 6661.8 – 6675.2 MHz (3),(6)
Ionized Helium Isotope (³HeII) 8665.650 MHz 8660.0 – 8670.0 MHz  
Methanol (CH₃OH) 12.178 GHz 12.17 – 12.19 GHz (3),(6)
Formaldehyde (H₂CO) 14.488 GHz 14.44 – 14.50 GHz (3),(4)
Cyclopropenylidene (C₃H₂) 18.343 GHz 18.28 – 18.36 GHz (3),(4),(6)
Water Vapour (H₂O) 22.235 GHz 22.16 – 22.26 GHz (3),(4)
Ammonia (NH₃) 23.694 GHz 23.61 – 23.71 GHz (4)
Ammonia (NH₃) 23.723 GHz 23.64 – 23.74 GHz (4)
Ammonia (NH₃) 23.870 GHz 23.79 – 23.89 GHz (4)
Silicon monoxide (SiO) 42.519 GHz 42.47 – 42.57 GHz (3)
Silicon monoxide (SiO) 42.821 GHz 42.77 – 42.86 GHz  
Silicon monoxide (SiO) 42.880 GHz 42.83 – 42.93 GHz  
Silicon monoxide (SiO) 43.122 GHz 43.07 – 43.17 GHz  
Silicon monoxide (SiO) 43.424 GHz 43.37 – 43.47 GHz  
Carbon monosulphide (CS) 48.991 GHz 48.94 – 49.04 GHz  
Deuterated formylium (DCO⁺) 72.039 GHz 71.96 – 72.11 GHz (3)
Silicon monoxide (SiO) 86.243 GHz 86.16 – 86.33 GHz  
Formylium (H¹³CO⁺) 86.754 GHz 86.66 – 86.84 GHz  
Silicon monoxide (SiO) 86.847 GHz 86.76 – 86.93 GHz  
Ethynyl radical (C₂H) 87.300 GHz 87.21 – 87.39 GHz (5)
Hydrogen cyanide (HCN) 88.632 GHz 88.34 – 88.72 GHz (4)
Formylium (HCO⁺) 89.189 GHz 88.89 – 89.28 GHz (4)
Hydrogen isocyanide (HNC) 90.664 GHz 90.57 – 90.76 GHz  
Diazenylium (N₂H) 93.174 GHz 93.07 – 93.27 GHz  
Carbon monosulphide (CS) 97.981 GHz 97.65 – 98.08 GHz (4)
Carbon monoxide (C¹⁸O) 109.782 GHz 109.67 – 109.89 GHz  
Carbon monoxide (C¹³CO) 110.201 GHz 109.83 – 110.31 GHz (4)
Carbon monoxide (C¹⁷O) 112.359 GHz 112.25 – 112.47 GHz (6)
Carbon monoxide (CO) 115.271 GHz 114.88 – 115.39 GHz (4)
Formaldehyde (H₂¹³CO) 137.450 GHz 137.31 – 137.59 GHz (3),(6)
Formaldehyde (H₂CO) 140.840 GHz 140.69 – 140.98 GHz  
Carbon monosulphide (CS) 146.969 GHz 146.82 – 147.12 GHz  
Water vapour (H₂O) 183.310 GHz 183.12 – 183.50 GHz  
Carbon monoxide (C¹⁸O) 219.560 GHz 219.34 – 219.78 GHz  
Carbon monoxide (C¹³CO) 220.399 GHz 219.67 – 220.62 GHz (4)
Carbon monoxide (CO) 230.538 GHz 229.77 – 230.77 GHz (4)
Carbon monosulphide (CS) 244.953 GHz 244.72 – 245.20 GHz (6)
Hydrogen cyanide (HCN) 265.886 GHz 265.62 – 266.15 GHz  
Formylium (HCO⁺) 267.557 GHz 267.29 – 267.83 GHz  
Hydrogen isocyanide (HNC) 271.981 GHz 271.71 – 272.25 GHz  
Dyazenulium (N₂H⁺) 279.511 GHz 279.23 – 279.79 GHz  
Carbon monoxide (C¹⁸O) 312.330 GHz 329.00 – 329.66 GHz  
Carbon monoxide (C¹³CO) 330.587 GHz 330.25 – 330.92 GHz  
Carbon monosulphide (CS) 342.883 GHz 342.54 – 343.23 GHz  
Carbon monoxide (CO) 345.796 GHz 345.45 – 346.14 GHz  
Hydrogen cyanide (HCN) 354.484 GHz 354.13 – 354.84 GHz  
Formylium (HCO⁺) 356.734 GHz 356.37 – 357.09 GHz  
Dyazenulium (N₂H⁺) 372.672 GHz 372.30 – 373.05 GHz  
Water vapour (H₂O) 380.197 GHz 379.81 – 380.58 GHz  
Carbon monoxide (C¹⁸O) 439.088 GHz 438.64 – 439.53 GHz  
Carbon monoxide (C¹³CO) 440.765 GHz 440.32 – 441.21 GHz  
Carbon monoxide (CO) 461.041 GHz 460.57 – 461.51 GHz  
Heavy water (HDO) 464.925 GHz 464.46 – 465.39 GHz  
Carbon (CI) 492.162 GHz 491.66 – 492.66 GHz  
Water vapour (H₂¹⁸O) 547.676 GHz 547.13 – 548.22 GHz  
Water vapour (H₂O) 556.936 GHz 556.37 – 557.50 GHz  
Ammonia (¹⁵NH₃) 572.113 GHz 571.54 – 572.69 GHz  
Ammonia (NH₃) 572.498 GHz 571.92 – 573.07 GHz  
Carbon monoxide (CO) 691.473 GHz 690.78 – 692.17 GHz  
Hydrogen cyanide (HCN) 797.433 GHz 796.64 – 789.23 GHz  
Formylium (HCO⁺) 802.653 GHz 801.85 – 803.85 GHz  
Carbon monoxide (CO) 806.652 GHz 805.85 – 807.46 GHz  
Carbon (CI) 809.350 GHz 808.54 – 810.16 GHz  
1): If Note 4) or Note 2) are not listed, the band limits are Doppler-shifted frequencies corresponding to radial velocities of +/- 300 km/s (consistent with line radiation occurring in our galaxy).
2): An extension to lower frequencies of the allocation of 1400-1427 MHz is required to allow for the Doppler shifts for HI observed in distant galaxies.
3): The current international allocation is not primary and/or does not meet bandwidth requirements. See: ITU-R Radio Regulations (Table 8) for more detailed information.
4): Because these line frequencies are also being used for observing other galaxies, the listed bandwidths include Doppler shifts corresponding to radial velocities of up to 1000 km/s. It should be noted that HI has been observed at frequencies redshifted to 500 MHz, while some lines of the most abundant molecules have been detected in galaxies with velocities up to 50 000 km/s, corresponding to a frequency reduction of up to 17%.
5): There are six closely spaced lines associated with this molecule at this frequency. The listed band is wide enough to permit observations of all six lines.
6): This line is not mentioned in Article 8 of the ITU-R Radio Regulations.

2. Supplementary list of important spectral lines of the IUCAF mm-wave working group

In preparation for the World Radiocommunication Conference 2000 (WRC-2000), which revised allocations above 71 GHz, the IUCAF mm-wavelengths Working Group examined all known transitions in the millimetre and sub-millimetre wavelengths. It selected a limited number of the most important astrophysical spectral lines.
This list supplements earlier lists, such as that produced by the International Astronomical Union, IAU, (see above), and is to be used for the allocation of frequency bands to the Radio Astronomy Service.

Substance Rest Frequency Suggested Minimum Bandwidth
Deuterium (DI) 327.348 MHz 327.0 – 327.7 MHz
Hydrogen (HI) 1420.406 MHz 1370.0 – 1427.0 MHz
Hydroxyl radical (OH) 1612.231 MHz 1606.8 – 1613.8 MHz
Hydroxyl radical (OH) 1665.402 MHz 1659.8 – 1667.1 MHz
Hydroxyl radical (OH) 1667.359 MHz 1661.8 – 1669.0 MHz
Hydroxyl radical (OH) 1720.530 MHz 1714.8 – 1722.2 MHz
Methyladyne (CH) 3263.794 MHz 3242.4 – 3267.1 MHz
Methyladyne (CH) 3335.481 MHz 3324.4 – 3338.8 MHz
Methyladyne (CH) 3349.193 MHz 3338.0 – 3352.5 MHz
Formaldehyde (H2CO) 4829.660 MHz 4813.6 – 4834.5 MHz
Methanol (CH3OH) 6668.518 MHz 6661.8 – 6675.2 MHz
Helium (3He+) 8665.650 MHz 8657.0 – 8674.3 MHz
Methanol (CH3OH) 12.178 GHz 12.17 – 12.19 GHz
Formaldehyde (H2CO) 14.488 GHz 14.44 – 14.50 GHz
Cyclopropenylidene (C3H2) 18.343 GHz 18.28 – 18.36 GHz
Cyclopropenylidene (C3H2) 21.587 GHz 21.56 – 21.61 GHz
Water vapor (H2O) 22.235 GHz 22.16 – 22.26 GHz
Dicarbon monosulphide (CCS) 22.344 GHz 22.32 – 22.37 GHz
Ammonia (NH3) 23.694 GHz 23.61 – 23.72 GHz
Ammonia (NH3) 23.723 GHz 23.64 – 23.75 GHz
Ammonia (NH3) 23.870 GHz 23.79 – 23.89 GHz
Ammonia (NH3) 24.139 GHz 24.11 – 24.16 GHz
Methanol (CH3OH) 36.169 GHz 36.13 – 36.21 GHz
Cyanoacetylene (HC3N) 36.392 GHz 36.36 – 36.43 GHz
Silicon monoxide (SiO) 42.519 GHz 42.47 – 42.57 GHz
Silicon monoxide (SiO) 42.821 GHz 42.77 – 42.86 GHz
Silicon monoxide (SiO) 42.880 GHz 42.83 – 42.93 GHz
Silicon monoxide (SiO) 43.122 GHz 43.07 – 43.17 GHz
Silicon monoxide (SiO) 43.424 GHz 43.37 – 43.47 GHz
Dicarbon monosulphide (CCS) 45.379 GHz 45.33 – 45.42 GHz
Cyanoacetylene (HC3N) 45.490 GHz 45.44 – 45.54 GHz
Carbon monosulphide (13CS) 46.247 GHz 46.20 – 46.29 GHz
Carbon monosulphide (C34S) 48.207 GHz 48.16 – 48.26 GHz
Carbon monosulphide (CS) 48.991 GHz 48.83 – 49.04 GHz
Oxygen (O2) 56.265 GHz 56.21 – 56.32 GHz
Oxygen (O2) 58.324 GHz 58.27 – 58.38 GHz
Oxygen (O2) 58.446 GHz 58.39 – 58.50 GHz
Oxygen (O2) 59.164 GHz 59.10 – 59.22 GHz
Oxygen (O2) 59.591 GHz 59.53 – 59.65 GHz
Oxygen (O2) 60.306 GHz 60.25 – 60.37 GHz
Oxygen (O2) 60.434 GHz 60.37 – 60.49 GHz
Oxygen (O2) 61.151 GHz 61.09 – 61.21 GHz
Oxygen (O2) 62.486 GHz 62.42 – 62.55 GHz
Deuterated formylium (DCO+) 72.039 GHz 71.97 – 72.11 GHz
Deuterium cyanide (DCN) 72.415 GHz 72.34 – 72.49 GHz
Cyanoacetylene (HC3N) 72.784 GHz 72.71 – 72.86 GHz
Methyl cyanide (CH3CN) 73.59 GHz 73.51 – 73.66 GHz
Deuterated water (HDO) 80.578 GHz 80.50 – 80.66 GHz
Cyanoacetylene (HC3N) 81.881 GHz 81.80 – 81.96 GHz
Cyclopropenylidene (C3H2) 82.966 GHz 82.88 – 83.05 GHz
Cyclopropenylidene (C3H2) 85.339 GHz 85.05 – 85.42 GHz
Methyl acetylene (CH3CCH) 85.5 GHz 85.41 – 85.59 GHz
Deuterated Ammonia (NH2D) 85.926 GHz 85.84 – 86.01 GHz
Hydrogen cyanide (HC15N) 86.055 GHz 85.97 – 86.14 GHz
Silicon monoxide (SiO) 86.243 GHz 86.16 – 86.33 GHz
Hydrogen cyanide (H13CN) 86.340 GHz 86.25 – 86.43 GHz
Formylium (H13CO+) 86.754 GHz 86.67 – 86.84 GHz
Hydrogen isocyanide (HN13C) 87.091 GHz 87.00 – 87.18 GHz
Silicon monoxide (SiO) 86.847 GHz 86.76 – 86.93 GHz
Ethynyl radical (C2H) 87.300 GHz 87.21 – 87.39 GHz
Hydrogen cyanide (HCN) 88.632 GHz 88.34 – 88.72 GHz
Hydrogen isocyanide (H15NC) 88.866 GHz 88.78 – 88.95 GHz
Formylium (HCO+) 89.189 GHz 88.89 – 89.28 GHz
Hydrogen isocyanide (HNC) 90.664 GHz 90.57 – 90.75 GHz
Cyanoacetylene (HC3N) 90.979 GHz 90.89 – 91.07 GHz
Methyl cyanide (CH3CN) 91.98 GHz 91.88 – 92.07 GHz
Carbon monosulphide (13CS) 92.494 GHz 92.40 – 92.59 GHz
Diazenylium (N2H+) 93.174 GHz 93.08 – 93.27 GHz
Carbon monosulphide (C34S) 96.413 GHz 96.32 – 96.51 GHz
Carbon monosulphide (CS) 97.981 GHz 97.65 – 98.08 GHz
Sulphur monoxide (SO) 99.300 GHz 99.20 – 99.40 GHz
Cyanoacetylene (HC3N) 100.076 GHz 99.98 – 100.18 GHz
Methyl acetylene (CH3CCH) 102.5 GHz 102.39 – 102.60 GHz
Cyanoacetylene (HC3N) 109.174 GHz 109.06 – 109.28 GHz
Sulphur monoxide (SO) 109.252 GHz 109.14 – 109.36 GHz
Carbon monoxide (C18O) 109.782 GHz 109.67 – 109.89 GHz
Deuterated Ammonia (NH2D) 110.153 GHz 110.04 – 110.26 GHz
Carbon monoxide (13CO) 110.201 GHz 119.83 – 110.31 GHz
Methyl cyanide (CH3CN) 110.38 GHz 110.27 – 110.49 GHz
Carbon monoxide (C17O) 112.359 GHz 112.25 – 112.47 GHz
Cyano radical (CN) 113.500 GHz 113.39 – 113.61 GHz
Carbon monoxide (CO) 115.271 GHz 114.88 – 115.39 GHz
Oxygen (O2) 118.750 GHz 118.63 – 118.87 GHz
Silicon monoxide (SiO) 127.269 GHz 127.14 – 127.40 GHz
Formaldehyde (H213CO) 137.450 GHz 137.31 – 137.59 GHz
Carbon monosulphide (13CS) 138.739 GHz 138.60 – 138.88 GHz
Formaldehyde (H2CO) 140.840 GHz 140.69 – 140.98 GHz
Deuterated formylium (DCO+) 144.077 GHz 143.93 – 144.22 GHz
Deuterium cyanide (DCN) 144.828 GHz 144.68 – 144.97 GHz
Formaldehyde (H2CO) 145.603 GHz 145.45 – 145.75 GHz
Carbon monosulphide (CS) 146.969 GHz 146.48 – 147.12 GHz
Methyl cyanide (CH3CN) 147.17 GHz 147.02 – 147.32 GHz
Nitric oxide (NO) 150.4 GHz 149.95 – 150.85 GHz
Formaldehyde (H2CO) 150.498 GHz 150.35 – 150.65 GHz
Methyl acetylene (CH3CCH) 153.8 GHz 153.64 – 153.95 GHz
Cyanoacetylene (HC3N) 154.657 GHz 154.50 – 154.81 GHz
Cyanoacetylene (HC3N) 163.753 GHz 163.59 – 163.92 GHz
Hydrogen sulphide (H2S) 168.760 GHz 168.59 – 168.93 GHz
Silicon monoxide (SiO) 173.688 GHz 173.51 – 173.86 GHz
Water vapor (H2O) 183.310 GHz 183.13 – 183.49 GHz
Carbon monosulphide (CS) 195.954 GHz 195.30 – 196.15 GHz
Water vapor (H218O) 203.132 GHz 202.93 – 203.34 GHz
Sulphur monoxide (SO) 206.176 GHz 205.97 – 206.38 GHz
Sulphur monoxide (SO) 215.221 GHz 215.01 – 215.44 GHz
Deuterated formylium (DCO+) 216.113 GHz 215.90 – 216.33 GHz
Silicon monoxide (SiO) 217.105 GHz 216.89 – 217.32 GHz
Deuterium cyanide (DCN) 217.239 GHz 217.02 – 217.46 GHz
Formaldehyde (H2CO) 218.222 GHz 218.00 – 218.44 GHz
Carbon monoxide (C18O) 219.560 GHz 219.34 – 219.78 GHz
Carbon monoxide (13CO) 220.399 GHz 219.67 – 220.62 GHz
Methyl cyanide (CH3CN) 220.7 GHz 220.48 – 220.92 GHz
Sulphur dioxide (SO2) 221.965 GHz 221.74 – 222.19 GHz
Methyl acetylene (CH3CCH) 222.1 GHz 221.87 – 222.32 GHz
Carbon monoxide (C17O) 224.714 GHz 224.49 – 224.94 GHz
Sulphur dioxide (SO2) 225.154 GHz 224.93 – 225.38 GHz
Deuterated water (HDO) 225.897 GHz 225.67 – 226.12 GHz
Cyano radical (CN) 226.600 GHz 226.37 – 226.83 GHz
Cyano radical (CN) 226.800 GHz 226.57 – 227.03 GHz
Carbon monoxide (CO) 230.538 GHz 229.77 – 230.77 GHz
Carbon monosulphide (13CS) 231.221 GHz 230.99 – 231.45 GHz
Carbon monosulphide (C34S) 241.016 GHz 240.77 – 241.26 GHz
Deuterated water (HDO) 241.562 GHz 241.32 – 241.80 GHz
Methanol (CH3OH) 241.700 GHz 241.46 – 241.94 GHz
Methanol (CH3OH) 241.767 GHz 241.53 – 242.01 GHz
Methanol (CH3OH) 241.791 GHz 241.55 – 242.03 GHz
Methanol (CH3OH) 241.842 GHz 241.60 – 242.08 GHz
Carbon monosulphide (CS) 244.953 GHz 244.14 – 245.20 GHz
Nitric oxide (NO) 250.6 GHz 250.35 – 250.85 GHz
Sulphur dioxide (SO2) 251.211 GHz 250.96 – 251.46 GHz
Methyl cyanide (CH3CN) 257.5 GHz 257.24 – 257.76 GHz
Hydrogen cyanide (H13CN) 259.012 GHz 258.75 – 259.27 GHz
Formylium (H13CO+) 260.255 GHz 259.99 – 260.52 GHz
Silicon monoxide (SiO) 260.518 GHz 260.26 – 260.78 GHz
Hydrogen isocyanide (HN13C) 261.263 GHz 261.00 – 261.52 GHz
Ethynyl radical (C2H) 262.000 GHz 261.74 – 262.26 GHz
Sulphur dioxide (SO2) 262.334 GHz 262.07 – 262.60 GHz
Hydrogen cyanide (HCN) 265.886 GHz 265.00 – 266.15 GHz
Formylium (HCO+) 267.557 GHz 266.66 – 267.82 GHz
Hydrogen isocyanide (HNC) 271.981 GHz 271.71 – 272.25 GHz
Carbon monosulphide (13CS) 277.455 GHz 277.18 – 277.73 GHz
Diazenylium (N2H+) 279.511 GHz 279.23 – 279.79 GHz
Carbon monosulphide (C34S) 289.209 GHz 288.92 – 289.50 GHz
Sodium hydride (NaH) 289.860 GHz 289.57 – 290.15 GHz
Carbon monosulphide (CS) 293.912 GHz 292.93 – 294.21 GHz
Hydronium (H3O+) 307.192 GHz 306.88 – 307.50 GHz
Carbon monosulphide (13CS) 323.685 GHz 323.36 – 324.01 GHz
Water vapor (H2O) 325.153 GHz 324.83 – 325.48 GHz
Heavy water (HDO) 313.750 GHz 313.44 – 314.06 GHz
Carbon monoxide (C18O) 329.330 GHz 329.00 – 329.66 GHz
Carbon monoxide (13CO) 330.587 GHz 329.49 – 330.92 GHz
Carbon monosulphide (C34S) 337.397 GHz 337.06 – 337.73 GHz
Cyano radical (CN) 340.030 GHz 339.69 – 340.37 GHz
Cyano radical (CN) 340.250 GHz 339.91 – 340.59 GHz
Carbon monosulphide (CS) 342.883 GHz 341.74 – 343.23 GHz
Hydrogen cyanide (HC15N) 344.200 GHz 343.86 – 344.54 GHz
Magnesium hydride (MgH) 344.305 GHz 343.96 – 344.65 GHz
Hydrogen cyanide (H13CN) 344.340 GHz 344.00 – 344.68 GHz
Carbon monoxide (CO) 345.796 GHz 344.64 – 346.14 GHz
Formylium (H13CO+) 346.999 GHz 346.65 – 347.35 GHz
Silicon monoxide (SiO) 347.331 GHz 346.98 – 347.68 GHz
Ethynyl radical (C2H) 349.340 GHz 348.99 – 349.69 GHz
Ethynyl radical (C2H) 349.390 GHz 349.04 – 349.74 GHz
Hydrogen cyanide (HCN) 354.484 GHz 353.30 – 354.84 GHz
Formylium (HCO+) 356.734 GHz 355.54 – 357.09 GHz
Hydrogen isocyanide (HNC) 362.630 GHz 362.27 – 362.99 GHz
Hydronium (H3O+) 364.797 GHz 364.43 – 365.16 GHz
Oxygen (O2) 368.498 GHz 368.13 – 368.87 GHz
Carbon monosulphide (13CS) 369.908 GHz 369.54 – 370.28 GHz
H2D+ 372.421 GHz 372.05 – 372.79 GHz
Diazenylium (N2H+) 372.672 GHz 372.30 – 373.04 GHz
Water vapor (H2O) 380.197 GHz 379.82 – 380.58 GHz
Carbon monosulphide (C34S) 385.578 GHz 385.19 – 385.96 GHz
Hydronium (H3O+) 388.459 GHz 388.07 – 388.85 GHz
Water vapor (H218O) 390.608 GHz 390.22 – 391.00 GHz
Silicon monoxide (SiO) 390.728 GHz 390.34 – 391.12 GHz
Carbon monosulphide (CS) 391.847 GHz 390.54 – 392.24 GHz
Hydronium (H3O+) 396.272 GHz 395.88 – 396.67 GHz
Carbon monosulphide (13CS) 416.123 GHz 415.71 – 416.54 GHz
Oxygen (O2) 424.763 GHz 424.34 – 425.19 GHz
Hydrogen cyanide (H13CN) 431.660 GHz 431.23 – 432.09 GHz
Carbon monosulphide (C34S) 433.751 GHz 433.32 – 434.19 GHz
Silicon monoxide (SiO) 434.120 GHz 433.69 – 434.55 GHz
Carbon monoxide (C18O) 439.088 GHz 438.65 – 439.53 GHz
Water vapor (H2O) 439.151 GHz 438.71 – 439.59 GHz
Carbon monoxide (13CO) 440.765 GHz 439.30 – 441.21 GHz
Carbon monosulphide (CS) 440.803 GHz 439.33 – 441.24 GHz
Hydrogen cyanide (HCN) 443.123 GHz 441.65 – 443.57 GHz
Lithium hydride (LiH) 443.957 GHz 443.51 – 444.40 GHz
Water vapor (H2O) 448.001 GHz 447.55 – 448.45 GHz
Hyrogen Sulphide (H2S) 452.390 GHz 451.94 – 452.84 GHz
Hydrogen isocyanide (HNC) 453.270 GHz 452.82 – 453.72 GHz
Carbon monoxide (CO) 461.041 GHz 459.50 – 461.50 GHz
Carbon monosulphide (13CS) 462.331 GHz 461.87 – 462.79 GHz
NH2 462.400 GHz 461.94 – 462.86 GHz
Heavy water (HDO) 464.925 GHz 464.46 – 465.39 GHz
NH2 469.300 GHz 468.83 – 469.77 GHz
Water vapor (H2O) 474.689 GHz 474.21 – 475.16 GHz
Silicon monoxide (SiO) 477.503 GHz 477.03 – 477.98 GHz
Heavy water (HDO) 479.947 GHz 479.47 – 480.43 GHz
Heavy water (HDO) 481.780 GHz 481.30 – 482.26 GHz
Carbon monosulphide (C34S) 481.916 GHz 481.43 – 482.40 GHz
Oxygen (O2) 487.249 GHz 486.76 – 487.74 GHz
Water vapor (H218O) 489.054 GHz 488.56 – 489.54 GHz
Carbon monosulphide (CS) 489.751 GHz 488.12 – 490.24 GHz
Heavy water (HDO) 490.597 GHz 490.11 – 491.09 GHz
Carbon (CI) 492.162 GHz 490.52 – 492.65 GHz
Carbon monosulphide (13CS) 508.528 GHz 508.02 – 509.04 GHz
Heavy water (HDO) 509.292 GHz 508.78 – 509.80 GHz
Hydrogen cyanide (H13CN) 517.970 GHz 517.45 – 518.49 GHz
Silicon monoxide (SiO) 520.878 GHz 520.36 – 521.40 GHz
Carbon monosulphide (C34S) 530.071 GHz 529.54 – 530.60 GHz
Hydrogen cyanide (HCN) 531.716 GHz 529.94 – 532.25 GHz
Methylidyne (CH) 532.700 GHz 532.17 – 533.23 GHz
SiH2 536.600 GHz 536.06 – 537.14 GHz
Methylidyne (CH) 536.800 GHz 536.26 – 537.34 GHz
Carbon monosulphide (CS) 538.689 GHz 536.89 – 539.23 GHz
Hydrogen isocyanide (HNC) 543.897 GHz 543.35 – 544.44 GHz
Water vapor (H218O) 547.676 GHz 547.13 – 548.22 GHz
Carbon monoxide (13CO) 550.926 GHz 549.09 – 551.48 GHz
Carbon monosulphide (13CS) 554.715 GHz 554.16 – 555.27 GHz
Water vapor (H2O) 556.936 GHz 556.38 – 557.49 GHz
Silicon monoxide (SiO) 564.244 GHz 563.68 – 564.81 GHz
Ammonia (15NH3) 572.113 GHz 571.54 – 572.69 GHz
Ammonia (NH3) 572.498 GHz 571.93 – 573.07 GHz
SiH2 575.800 GHz 575.22 – 576.38 GHz
Carbon monoxide (CO) 576.268 GHz 574.35 – 576.84 GHz
Carbon monosulphide (C34S) 578.216 GHz 577.64 – 578.79 GHz
Sodium Hydride (NaH) 579.480 GHz 578.90 – 580.06 GHz
Carbon monosulphide (CS) 587.616 GHz 587.03 – 588.20 GHz
Heavy water (HDO) 599.927 GHz 599.33 – 600.53 GHz
Carbon monosulphide (13CS) 600.889 GHz 600.29 – 601.49 GHz
Hydrogen cyanide (H13CN) 604.268 GHz 603.66 – 604.87 GHz
Silicon monoxide (SiO) 607.599 GHz 606.99 – 608.21 GHz
Hydrogen cyanide (HCN) 620.304 GHz 618.24 – 620.92 GHz
Water vapor (H2O) 620.700 GHz 620.08 – 621.32 GHz
Heavy water (HDO) 622.483 GHz 621.86 – 623.11 GHz
Silicon hydride (SiH) 624.900 GHz 624.27 – 625.53 GHz
Hydrogen chloride (HCl) 625.040 GHz 624.41 – 625.67 GHz
Hydrogen chloride (HCl) 625.980 GHz 625.35 – 626.61 GHz
Carbon monosulphide (C34S) 626.349 GHz 625.72 – 626.98 GHz
Silicon hydride (SiH) 627.700 GHz 627.07 – 628.33 GHz
Hydrogen isocyanide (HNC) 634.510 GHz 633.88 – 635.14 GHz
Carbon monosulphide (CS) 636.532 GHz 634.41 – 637.17 GHz
Carbon monosulphide (13CS) 647.050 GHz 646.40 – 647.70 GHz
H2D+ 648.337 GHz 647.69 – 648.99 GHz
Silicon monoxide (SiO) 650.944 GHz 650.29 – 651.60 GHz
Carbon monoxide (13CO) 661.067 GHz 658.86 – 661.73 GHz
Carbon monosulphide (C34S) 674.470 GHz 673.80 – 675.14 GHz
Carbon monosulphide (CS) 685.435 GHz 683.15 – 686.12 GHz
Magnesium hydride (MgH) 687.100 GHz 686.41 – 687.79 GHz
Magnesium hydride (MgH) 687.900 GHz 687.21 – 688.59 GHz
Hydrogen cyanide (H13CN) 690.268 GHz 689.58 – 690.96 GHz
Carbon monoxide (CO) 691.473 GHz 689.17 – 692.16 GHz
Carbon monosulphide (13CS) 693.195 GHz 692.50 – 693.89GHz
Silicon monoxide (SiO) 694.275 GHz 693.58 – 694.97 GHz
Hydrogen cyanide (HCN) 708.877 GHz 708.17 – 709.59 GHz
Oxygen (O2) 715.393 GHz 714.68 – 716.11 GHz
Carbon monosulphide (C34S) 722.577 GHz 721.85 – 723.30 GHz
Hydrogen isocyanide (HNC) 725.107 GHz 724.38 – 725.83 GHz
Carbon monosulphide (CS) 734.324 GHz 733.59 – 735.06 GHz
Silicon monoxide (SiO) 737.594 GHz 736.86 – 738.33 GHz
Carbon monosulphide (13CS) 739.324 GHz 738.58 – 740.06 GHz
Water vapor (H218O) 745.320 GHz 744.57 – 746.07 GHz
Water vapor (H2O) 752.033 GHz 751.28 – 752.79 GHz
Heavy water (HDO) 753.411 GHz 752.66 – 754.16 GHz
Carbon monosulphide (C34S) 770.669 GHz 769.90 – 771.44 GHz
Oxygen (O2) 773.840 GHz 773.07 – 774.61 GHz
Hydrogen cyanide (H13CN) 776.819 GHz 776.04 – 777.60 GHz
Silicon monoxide (SiO) 780.594 GHz 779.81 – 781.38 GHz
Carbon monosulphide (CS) 783.199 GHz 782.42 – 783.98 GHz
Carbon monosulphide (13CS) 785.434 GHz 784.65 – 786.22 GHz
Hydrogen cyanide (HCN) 797.433 GHz 794.77 – 798.23 GHz
Formylium (HCO+) 802.653 GHz 799.98 – 803.46 GHz
Carbon monoxide (CO) 806.652 GHz 803.96 – 807.46 GHz
Carbon (CI) 809.350 GHz 806.65 – 810.16 GHz
Hydrogen isocyanide (HNC) 815.684 GHz 812.96 – 816.50 GHz
Carbon monosulphide (C34S) 818.745 GHz 817.93 – 819.56 GHz
Silicon monoxide (SiO) 824.186 GHz 823.36 – 825.01 GHz
Carbon monosulphide (13CS) 831.523 GHz 830.69 – 832.36 GHz
Carbon monosulphide (CS) 832.057 GHz 829.28 – 832.89 GHz
Oxygen (O2) 834.146 GHz 833.31 – 834.98 GHz
Methylidinium (CH+) 835.070 GHz 834.23 – 835.91 GHz
Hydrogen cyanide (H13CN) 863.069 GHz 862.21 – 863.93 GHz
Carbon monosulphide (C34S) 866.804 GHz 865.94 – 867.67 GHz
Sulpher hydride (SH) 866.900 GHz 866.03 – 867.77 GHz
Silicon monoxide (SiO) 867.457 GHz 866.59 – 868.33 GHz
Sulpher hydride (SH) 875.200 GHz 874.32 – 876.08 GHz
Carbon monosulphide (13CS) 877.591 GHz 876.71 – 878.47 GHz
Carbon monosulphide (CS) 880.899 GHz 877.96 – 881.78 GHz
Carbon monoxide (13CO) 881.273 GHz 878.33 – 882.15 GHz
Hydrogen cyanide (HCN) 885.977 GHz 883.02 – 886.86 GHz
Lithium hydride (LiH) 886.500 GHz 885.61 – 887.39 GHz
Formilium (HCO+) 891.558 GHz 888.59 – 892.45 GHz
Heavy water (HDO) 893.639 GHz 892.74 – 894.53 GHz
Hydrogen isocyanide (HNC) 906.239 GHz 905.33 – 907.15 GHz
Silicon monoxide (SiO) 910.710 GHz 909.80 – 911.62 GHz
Carbon monosulphide (C34S) 914.844 GHz 913.93 – 915.76 GHz
Water vapor (H2O) 916.172 GHz 915.26 – 917.09 GHz
Heavy water (HDO) 919.310 GHz 918.39 – 920.23 GHz
Carbon monoxide (CO) 921.800 GHz 918.72 – 922.72 GHz
Carbon monosulphide (13CS) 923.633 GHz 922.71 – 924.56 GHz
Carbon monosulphide (CS) 929.723 GHz 926.62 – 930.65 GHz
Hydrogen cyanide (H13CN) 949.299 GHz 948.35 – 950.25 GHz
Silicon monoxide (SiO) 953.943 GHz 952.99 – 954.90 GHz
H3+ 955.000 GHz 954.04 – 955.96 GHz
Carbon monosulphide (C34S) 962.865 GHz 961.90 – 963.83 GHz
Carbon monosulphide (13CS) 969.649 GHz 968.68 – 970.62 GHz
Water vapor (H2O) 970.315 GHz 969.34 – 971.29 GHz
Nitrogen hydride (NH) 974.479 GHz 973.50 – 975.45 GHz
Hydrogen cyanide (HCN) 974.488 GHz 971.24 – 975.46 GHz
Carbon monosulphide (CS) 978.529 GHz 977.55 – 979.51 GHz
Formilium (HCO+) 983.925 GHz 980.64 – 984.91 GHz
Heavy water (HDO) 984.138 GHz 983.15 – 985.12 GHz
Hydronium (H3O+) 984.697 GHz 983.71 – 985.68 GHz
Water vapor (H2O) 987.927 GHz 986.94 – 988.92 GHz
Water vapor (H218O) 994.634 GHz 993.64 – 995.63 GHz
Heavy water (HDO) 995.412 GHz 994.42 – 996.41 GHz
Hydrogen isocyanide (HNC) 996.771 GHz 995.77 – 997.77 GHz
Silicon monoxide (SiO) 997.155 GHz 996.16 – 998.15 GHz

Committee on Radio Astronomy Frequencies