The rotational spectrum of the formaldehyde isotopologue H _ { 2 } C ^ { 17 } O was investigated between 0.56 and 1.50 THz using a sample of natural isotopic composition .
In addition , transition frequencies were determined for H _ { 2 } C ^ { 18 } O and H _ { 2 } C ^ { 16 } O between 1.37 and 1.50 THz .
The data were combined with critically evaluated literature data to derive improved sets of spectroscopic parameters which include ^ { 17 } O or H nuclear hyperfine structure parameters .