Houk, Amanda L.Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
Author
Krylov, Anna I.Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
Author
Elles, Christopher G.Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
Author
Abstract
Two-photon absorption (2PA) spectroscopy provides complementary, and sometimes more detailed, information about the electronic structure of a molecule relative to one-photon absorption (1PA) spectroscopy. However, our understanding of the 2PA processes is rather limited due to technical difficulties in measuring experimental 2PA spectra and theoretical challenges in computing higherorder molecular properties. This paper examines the 2PA spectroscopy of trans-stilbene, cis-stilbene, and phenanthrene by a combined experimental and theoretical approach. The broadband 2PAspectra of all three compounds are measured under identical conditions in order to facilitate a direct comparison of the absolute 2PA cross sections in the range 3.5-6.0 eV. For comparison, the theoretical 2PA cross sections are computed using the equation-of-motion coupled-cluster method with single and double substitutions. Simulated 2PA spectra based on the calculations reproduce the main features of the experimental spectra in solution, although the quantitative comparison is complicated by a number of uncertainties, including limitations of the theoretical model, vibronic structure, broadening of the experimental spectra, and solvent effects. The systematic comparison of experimental and theoretical spectra for this series of structurally similar compounds provides valuable insight into the nature of 2PA transitions in conjugated molecules. Notably, the orbital character and symmetry-based selection rules provide a foundation for interpreting the features of the experimental 2PA spectra in unprecedented detail. Published by AIP Publishing.
de Wergifosse, M., Houk, A. L., Krylov, A. I., & Elles, C. G. (2017). Two-photon absorption spectroscopy of trans-stilbene, cis-stilbene, and phenanthrene: Theory and experiment. Journal of Chemical Physics, 146(14). https://doi.org/10.1063/1.4979651 (Original work published 2017)