Related Experiment Video
Updated: Apr 7, 2026

Measuring Diffusion Coefficients via Two-photon Fluorescence Recovery After Photobleaching
Published on: February 26, 2010
Benchmarking two-photon absorption cross sections: performance of CC2 and CAM-B3LYP
Maarten T P Beerepoot1, Daniel H Friese, Nanna H List
1Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø-The Arctic University of Norway, N-9037 Tromsø, Norway. maarten.beerepoot@uit.no.
Abstract:
We investigate the performance of CC2 and TDDFT/CAM-B3LYP for the calculation of two-photon absorption (TPA) strengths and cross sections and contrast our results to a recent coupled cluster equation-of-motion (EOM-EE-CCSD) benchmark study [K. D. Nanda and A. I. Krylov, J. Chem. Phys., 2015, 142, 064118]. In particular, we investigate whether CC2 TPA strengths are significantly overestimated compared to higher-level coupled-cluster calculations for fluorescent protein chromophores. Our conclusion is that CC2 TPA strengths are only slightly overestimated compared to the reference EOM-EE-CCSD results and that previously published overestimated cross sections are a result of inconsistencies in the conversion of the TPA strengths to macroscopic units. TDDFT/CAM-B3LYP TPA strengths, on the other hand, are found to be 1.5 to 3 times smaller than the coupled-cluster reference for the molecular systems considered. The unsatisfactory performance of TDDFT/CAM-B3LYP can be linked to an underestimation of excited-state dipole moments predicted by TDDFT/CAM-B3LYP.
More Related Videos
Related Concept Videos
Molecular Spectroscopy: Absorption and Emission
Atomic Absorption Spectroscopy: Radiation and Light Sources
Two common narrow-range 'line' sources used in AAS are hollow-cathode lamps (HCLs) and...
UV–Vis Spectroscopy: Beer–Lambert Law
UV–Vis Spectroscopy: Molecular Electronic Transitions

