Jump to main content
Jump to site search

Issue 1, 2014
Previous Article Next Article

Electronically excited states and photochemical reaction mechanisms of β-glucose

Author affiliations

Abstract

Carbohydrates are important molecular components of living matter. While spectroscopic and computational studies have been performed on carbohydrates in the electronic ground state, the lack of a chromophore complicates the elucidation of the excited-state properties and the photochemistry of this class of compounds. Herein, we report on the first computational investigation of the singlet photochemistry of β-glucose. It is shown that low-lying singlet excited states are of nσ* nature. Our computations of the singlet vertical excitation energies predict absorption from 6.0 eV onward. Owing to a dense manifold of weakly-absorbing states, a sizable and broad absorption in the ultraviolet-C range arises. We have explored two types of photochemical reaction mechanisms: hydrogen-detachment processes for each of the five O–H groups and a C–O ring-opening process. Both types of reactions are driven by repulsive nσ* states that are readily accessible from the Franck–Condon region and lead to conical intersections in a barrierless fashion. We have optimized the geometries of the conical intersections involved in these photochemical processes and found that these intersections are located around 5.0 eV for the O–H hydrogen-detachment reactions and around 4.0 eV for the C–O ring-opening reaction. The energies of all conical intersections are well below the computed absorption edge. The calculations were performed using linear-response methods for the computation of the vertical excitation energies and multiconfigurational methods for the optimization of conical intersections and the computation of energy profiles.

Graphical abstract: Electronically excited states and photochemical reaction mechanisms of β-glucose

Back to tab navigation

Supplementary files

Publication details

The article was received on 06 Jun 2013, accepted on 24 Jul 2013 and first published on 20 Aug 2013


Article type: Paper
DOI: 10.1039/C3CP52359D
Phys. Chem. Chem. Phys., 2014,16, 38-47

  •   Request permissions

    Electronically excited states and photochemical reaction mechanisms of β-glucose

    D. Tuna, A. L. Sobolewski and W. Domcke, Phys. Chem. Chem. Phys., 2014, 16, 38
    DOI: 10.1039/C3CP52359D

Search articles by author

Spotlight

Advertisements