So far I had no luck trying to find the visible absorption spectrum of CO₂ anywhere, all I get is the far infrared absorption spectrum and stuff like that.
If you just search "what color is liquid CO₂" it simply says everywhere that "it's colorless" but... That's also said a lot about other liquids such as water, but we all know that's not true. Water is not colorless at all, it just appears colorless in small quantities since it's a very transparent liquid, and one can only appreciate its slightly blue coloration in very large quantities such like in pools, lakes, oceans, etc. Water is not just blue because of Rayleigh scattering and the sky's reflection, it is also and mainly blue because it does in fact absorb more red and green light than it absorbs blue light, just like any other blue thing.
That being said, I don't think liquid CO₂ is colorless, I think it's just appears colorless in small quantities, but in very large quantities some color is perceivable, exactly just like it happens with water. But I might be totally wrong since that belief is based on absolutely nothing, that's simply how I guess it is since I have absolutely no idea and it's hard to imagine a liquid that totally ignores visible light lol
I had this question unanswered for a looong time, would love to finally get an answer.
Thanks in advance!