Tholins color and scattering

Question

One of the prevailing explanations for the reddish color of certain asteroids surfaces and planetary atmospheres, such as Jupiter's and Titan's, is the presence of complex polymeric molecules called tholins.

I understand that particles such as nitrogen molecules in Earth's atmosphere are small enough to interact with blue visible light and scatter it throughout the atmosphere. It also seems like some compounds of carbon appear green (diatomic carbon) and purple (C60 fullerenes) however I think that is mostly due to absorption instead of scattering.

Are tholins big enough to interact with red visible light and that causes their color? Can a subset of tholins be able to scatter different wavelength and produce more greenish hues?

Answer 1

Tholins don't create color by (freqyency-selective) scattering.

They are selective in absorbing light.

This is how they look like and work:

https://en.m.wikipedia.org/wiki/Polymethine_dyes

Of course, tholins are much more diverse. They are made by uv light indiscriminately cracking chemical bonds and letting the resulting ions and radicals interact with each other as they please. Most of them are colorless, but those that do have color are in general polymethine dyes.

p.s. neither the absorbtion nor scattering are directly related to molecule sizes.