Well, H, O and OH are not permanent gases, and can exist in extreme conditions only. I am even not sure that they can be separated from the molecules (H2, O2, H2O2, ..,) from which they are derived. This is probably the reason why few data are available, as these gases are probably extremely difficult to study in the conditions in which they are formed.

Aalin

You can estimate them using "The properties of gases and liquids" by Reid and Sherwood.

I think that Alain is correct. It needs some energy to dissociate H2 into two separate monoatomic H. Then still the equilibrium is practically completely on the side of H2 which means the two monoatomic H's will readily combine back to H2. The same applies for O2 and monoatomic O. Thus it would be impossible to separate pure monoatomic H or monoatomic O for the purposes of measurement of the thermodynamic properties, like critical properties and acentric factors (liquid vapor pressure needed). I think that it not possible even to estimate them with methods in book mentioned by Joao, I am very familiar with that book and its more recent editions. Probably the only way to determine those properties is indirectly with some model using mixtures, but one needs to know the exact amount of H and H2 etc in the mixture. I remember having seen the dissociation equilibrium of some of these in CRC Handbook of physics (?), but the temperature should be well over 1000 K to have any dissociation.

Thus I think that to model the thermodynamic properties of mixtures of gases in real conditions you don't need those monoatomic species, unless your real conditions means very high temperatures and possibly low pressures or some exotic conditions.