| Title: |
Probing ultrafast \pi\pi*/n\pi* internal conversion in organic chromophores via K-edge resonant absorption |
| Authors: |
Wolf, T. J. A., Myhre, R. H., Cryan, J. P., Coriani, S., Squibb, R. J., Battistoni, A., Berrah, N., Bostedt, C., Bucksbaum, P., Coslovich, G., Feifel, R., Gaffney, K. J., Grilj, J., Martinez, T. J., Miyabe, S., Moeller, S. P., Mucke, M., Natan, A., Obaid, R., Osipov, T., Plekan, O., Wang, S., Koch, H., Gühr, M. |
| Publication Year: |
2016 |
| Collection: |
Physics (Other) |
| Subject Terms: |
Physics - Chemical Physics |
| More Details: |
Organic chromophores with heteroatoms possess an important excited state relaxation channel from an optically allowed {\pi}{\pi}* to a dark n{\pi}*state. We exploit the element and site specificity of soft x-ray absorption spectroscopy to selectively follow the electronic change during the {\pi}{\pi}*/n{\pi}* internal conversion. As a hole forms in the n orbital during {\pi}{\pi}*/n{\pi}* internal conversion, the near edge x-ray absorption fine structure (NEXAFS) spectrum at the heteroatom K-edge exhibits an additional resonance. We demonstrate the concept with the nucleobase thymine, a prototypical heteroatomic chromophore. With the help of time resolved NEXAFS spectroscopy at the oxygen K-edge, we unambiguously show that {\pi}{\pi}*/n{\pi}* internal conversion takes place within (60 \pm 30) fs. High-level coupled cluster calculations on the isolated molecules used in the experiment confirm the superb electronic structure sensitivity of this new method for excited state investigations. |
| Document Type: |
Working Paper |
| DOI: |
10.1038/s41467-017-00069-7 |
| Access URL: |
http://arxiv.org/abs/1610.08498 |
| Accession Number: |
edsarx.1610.08498 |
| Database: |
arXiv |
