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Chemistry Forums for Students => Organic Chemistry Forum => Organic Spectroscopy => Topic started by: Ingeniosuccinimide on April 25, 2014, 07:16:40 AM

Title: Colours
Post by: Ingeniosuccinimide on April 25, 2014, 07:16:40 AM

Hello,

I had a brief discussion with one computational chemist who had no idea and I'd really like to know if there is some computational method or software that can be used to predict the color or absorption/emission λ_max of a compound solely on the basis of its structure (with omitting things like crystal system or particle size)?

I know there are Woodward-Hofmann empirical rules for UV spectroscopy, but I'm thinking of something newer or more precise involving quantum chemistry.

Title: Re: Colours
Post by: Corribus on April 25, 2014, 08:56:19 PM

Well there are certainly computational and theoretical methods to predict the absorption wavelength. Heck, you can use basic Huckel theory to get a rough estimate. Translating that into the color perceived by the human eye is a more difficult problem, and one that involves more than molecular properties. (Even the ambient light in a room, and possibly physiology, makes a difference to perceived color.)