Excited States of Xanthophylls Revisited: Towards the Simulation of Biologically Relevant Systems

23 June 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Xanthophylls are an important class of oxygen containing carotenoids, which play a fundamental role both in light harvesting pigment-protein complexes and in many other photo-responsive proteins. The complexity of the manifold of the electronic states and the large sensitivity to the environment still prevent a clear and coherent interpretation of their pho-tophysics and photochemistry. In this Letter, we first apply cutting-edge ab-initio methods (CC3, DMRG/NEVPT2) on model C2h keto-carotenoids to critically asses the performances +of single and multi-reference methods. We then lift symmetry restrictions and extend the tested methods to time dependent DFT and Semiempirical CI (SECI). From this analysis, we demonstrate that SECI can indeed represent an optimal method for describing light-induced processes of xanthophylls in biologically relevant systems. As an example, we investigate canthaxanthin in the Orange Carotenoid Protein showing that the conical intersections between excited states ...


Orange Carotenoid Protein

Supplementary materials

Supporting Information: Excited States of Xanthophylls Revisited: Towards the Simulation of Biologically Relevant
Methodological details on computational methods used; Numerical values of COn excitation energies at different levels of theory; Details on the fitting procedure performed on Bu+ CC3 excitation energies. Numerical values of interpolated and fitted excitation energies of COn ; MP2 optimized structures of C2h COn (n = 2 – 13), Comparison of excitation energies computed on CC3 and MP2 optimized structures. Comparison of BLA computed with different methods. Decomposition of DMRG-CASSCF wavefunctions of CO13 in Slater determinants. Mutual information diagrams for DMRG-CASSCF wavefunctions of CO13 . Converged DMRG-CASSCF active space molecu- lar orbitals of CO13 . Transition densities of CO13 computed at DMRG-SCF level and atTD-B3LYP level. Comparison of GS of CO11at different values of BLA computed at SECI level and at semiempirical HF level. Comparison of SECI excitation energies of CO11 at different values of BLA computed on MP2 and SECI optimized geometries. ...


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.