Calculation of the Vibrationally Resolved, Circularly Polarized Luminescence of d-Camphorquinone and (S,S)-trans-β-Hydrindanone

Graphical Abstract

Exciting times: The circularly polarized luminescence (CPL) of the first electronic excited states of d-camphorquinone and (S,S)-trans-β-hydrindanone is modeled by time-dependent density functional theory. The calculated CPL, absorption, emission (see picture), and circular dichroism spectra agree with experimental spectra in terms of band shape, width, and intensity.

Abstract

Circularly polarized luminescence (CPL), the differential emission of left- and right-handed circularly polarized light from a molecule, is modeled by using time-dependent density functional theory. Calculations of the CPL spectra for the first electronic excited states of d-camphorquinone and (S,S)-trans-β-hydrindanone under the Franck–Condon approximation and using various functionals are presented, as well as calculations of absorption, emission, and circular dichroism spectra. The functionals B3LYP, BHLYP, and CAM-B3LYP are employed, along with the TZVP and aug-cc-pVDZ Gaussian-type basis sets. For the lowest-energy transitions, all functionals and basis sets perform comparably, with the long-range-corrected CAM-B3LYP better reproducing the excitation energy of camphorquinone but leading to a blue shift with respect to experiment for hydrindanone. The vibrationally resolved spectra of camphorquinone are very well reproduced in terms of peak location, widths, shapes, and intensities. The spectra of hydrindanone are well reproduced in terms of overall envelope shape and width, as well as the lack of prominent vibrational structure in the emission and CPL spectra. Overall the simulated spectra compare well with experiment, and reproduce the band shapes, emission red shifts, and presence or absence of visible vibrational fine structure.