At the 21st general assembly of the IAU ( International Astronomical Union ) in 1991, significant spectral lines in radio astronomy are reviewed. IAU made the revision of lines from band, band edge and harmonic emissions, especially from space source transmitters.
Substance Rest Frequency Protected Segment Deuterium (DI) 327.3840 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 3252.9 - 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 (CH2OH) 6668.518 MHz 6661.8 - 6675.2 MHz Ionized Helium Isotope(3HeII) 8665.650 MHz 8660.0 - 8670.0 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 Water Vapour (H2O) 22.235 GHz 22.16 - 22.26 GHz Ammonia (NH3) 23.694 GHz 23.61 - 23.71 GHz Ammonia (NH3) 23.723 GHz 23.64 - 23.74 GHz Ammonia (NH3) 23.870 GHz 23.79 - 23.89 GHz Silicon monoxide (SiO) 42.821 GHz 42.77 - 42.86 GHz Silicon monoxide (SiO) 43.122 GHz 43.07 - 43.17 GHz Carbon monosulphide (CS) 48.991 GHz 48.94 - 49.04 GHz Deuterated formylium (DCO+) 72.039 GHz 71.96 - 72.11 GHz 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 Hydrogen cyanide (HCN) 88.632 GHz 88.34 - 88.72 GHz Formylium (HCO+) 89.189 GHz 88.89 - 89.28 GHz 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 Carbon monoxide (C18O) 109.782 GHz 109.67 - 109.89 GHz Carbon monoxide (13CO) 110.201 GHz 109.83 - 110.31 GHz Carbon monoxide (C17O) 112.359 GHz 112.25 - 112.47 GHz Carbon monoxide (CO) 115.271 GHz 114.88 - 115.39 GHz Formaldehyde (H213CO) 137.450 GHz 137.31 - 137.59 GHz 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 (13CO) 220.399 GHz 219.67 - 220.62 GHz Carbon monoxide (CO) 230.538 GHz 229.77 - 230.77 GHz Carbon monosulphide (CS) 244.953 GHz 244.72 - 245.20 GHz 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 (13CO) 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 (13CO) 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