It is said that because of bond-structures / possible vibrational states, non-greenhouse-gases / homonuclear diatomics cannot absorb IR.

Presumably there is no question that all gases, being matter, can and do emit (mostly) IR photons at familiar temperatures - whether-or-not composed of IR-active—dipole-moment molecules.

Why the asymmetry (emit but not absorb)? What am I missing or misunderstanding?

(Forgive any imprecise use of terms by this sincerely-curious non-practitioner of the art.)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.