Estimation of physiologically perceived color from TDDFT-derived excitation spectra

A new scheme for estimating the physiologically perceived color of a compound from its chemical structure is presented. The first step of this schema was the calculation of electronic excitation energies and probabilities. In this contribution, time-dependent Density Functional Theory (TDDFT) was used for this purpose. From the excitation energies and oscillator strengths, line shape was approximated by folding with Gaussian functions. Using this spectrum, the CIE1931 chromaticity coordinates were gained by numerical integration. The dependence of the chromaticity coordinates on the band width of the Gaussians was visualized in a chromaticity diagram. From this diagram, the color, as physiologically perceived by a human observer, was estimated. The approach was applied to nine textbook examples of dyes and its limitations are discussed critically. (C) 2004 Wiley Periodicals, Inc.