The DOI matches its Crossref record; 51 of the 51 references it cites were found in a registry or an index.
Internal conversion to the electronic ground state occurs via two distinct pathways for pyrimidine bases in aqueous solution
Open accessAbstract
The femtosecond transient absorption technique was used to study the relaxation of excited electronic states created by absorption of 267-nm light in all of the naturally occurring pyrimidine DNA and RNA bases in aqueous solution. The results reveal a surprising bifurcation of the initial excited-state population in <1 ps to two nonradiative decay channels within the manifold of singlet states. The first is the subpicosecond internal conversion channel first characterized in 2000. The second channel involves passage through a dark intermediate state assigned to a lowest-energy 1 nπ* state. Approximately 10–50% of all photoexcited pyrimidine bases decay via the 1 nπ* state, which has a lifetime of 10–150 ps. Three- to 6-fold-longer lifetimes are seen for pyrimidine nucleotides and nucleosides than for the corresponding free bases, revealing an unprecedented effect of ribosyl substitution on electronic energy relaxation. A small fraction of the 1 nπ* population is proposed to undergo intersystem crossing to the lowest triplet state in competition with vibrational cooling, explaining the higher triplet yields observed for pyrimidine versus purine bases at room temperature. Some simple correlations exist between yields of the 1 nπ* state and yields of some pyrimidine photoproducts, but more work is needed before the photochemical consequences of this state can be definitively determined. These findings lead to a dramatically different picture of electronic energy relaxation in single pyrimidine bases with important ramifications for understanding DNA photostability.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
Conical Intersections: Electronic Structure, Dynamics and Spectroscopy
Domcke, W., Yarkony, D. R., & Köppel, H. (2004) · Advanced Series in Physical Chemistry · doi:10.1142/5406 · Cited by 1,341
Ultrafast Excited-State Dynamics in Nucleic Acids
Crespo-Hernández, C. E., Cohen, B., Hare, P. M., & Kohler, B. (2004) · Chemical Reviews · doi:10.1021/cr0206770 · Cited by 1,278
Self-citationPotential energy surface crossings in organic photochemistry
Bernardi, F., Olivucci, M., & Robb, M. A. (1996) · Chemical Society Reviews · doi:10.1039/cs9962500321 · Cited by 818
Base stacking controls excited-state dynamics in A·T DNA
Crespo-Hernández, C. E., Cohen, B., & Kohler, B. (2005) · Nature · doi:10.1038/nature03933 · Cited by 461
Self-citationPecourt, J.-M. L., Peon, J., & Kohler, B. (2001) · Journal of the American Chemical Society · doi:10.1021/ja0161453 · Cited by 411
Self-citationCanuel, C., Mons, M., Piuzzi, F., Tardivel, B., Dimicoli, I., & Elhanine, M. (2005) · The Journal of Chemical Physics · doi:10.1063/1.1850469 · Cited by 407
Gustavsson, T., Bányász, Á., Lazzarotto, E., Markovitsi, D., Scalmani, G., Frisch, M. J., Barone, V., & Improta, R. (2006) · Journal of the American Chemical Society · doi:10.1021/ja056181s · Cited by 396
Intrinsic Lifetimes of the Excited State of DNA and RNA Bases
Kang, H., Lee, K. T., Jung, B., Ko, Y. J., & Kim, S. K. (2002) · Journal of the American Chemical Society · doi:10.1021/ja027627x · Cited by 375
Ullrich, S., Schultz, T., Zgierski, M. Z., & Stolow, A. (2004) · Physical Chemistry Chemical Physics · doi:10.1039/b316324e · Cited by 347
Perun, S., Sobolewski, A. L., & Domcke, W. (2005) · Journal of the American Chemical Society · doi:10.1021/ja044321c · Cited by 324
Cited by
DNA Excited-State Dynamics: From Single Bases to the Double Helix
Middleton, C. T., de La Harpe, K., Su, C., Law, Y. K., Crespo-Hernández, C. E., & Kohler, B. (2009) · Annual Review of Physical Chemistry · doi:10.1146/annurev.physchem.59.032607.093719 · Cited by 827
Self-citationThymine Dimerization in DNA Is an Ultrafast Photoreaction
Schreier, W. J., Schrader, T. E., Koller, F. O., Gilch, P., Crespo-Hernández, C. E., Swaminathan, V. N., Carell, T., Zinth, W., & Kohler, B. (2007) · Science · doi:10.1126/science.1135428 · Cited by 550
Self-citationImprota, R., Santoro, F., & Blancafort, L. (2016) · Chemical Reviews · doi:10.1021/acs.chemrev.5b00444 · Cited by 499
Relaxation mechanisms of UV-photoexcited DNA and RNA nucleobases
Barbatti, M., Aquino, A. J. A., Szymczak, J. J., Nachtigallová, D., Hobza, P., & Lischka, H. (2010) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1014982107 · Cited by 444
Progress and Challenges in the Calculation of Electronic Excited States
González, L., Escudero, D., & Serrano‐Andrés, L. (2012) · ChemPhysChem · doi:10.1002/cphc.201100200 · Cited by 429
Metadata
- Authors
- Hare, P. M., Crespo-Hernández, C. E., & Kohler, B.
- Venue
- Proceedings of the National Academy of Sciences
- Published
- 2007-01-09
- Volume
- 104
- Issue
- 2
- Pages
- 435-440
- ISSN
- 0027-8424 (ISSN-L)
- 1091-6490
- OpenAlex
- W2088771641
- Cited by
- 314
- References
- 51
- FWCI
- 12.36
- Type
- journal article
- Language
- en
- Open access
- green
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
How to cite
Cite CoChat for the checks on this page, and the paper for its own findings.
- This page
- CoChat. (2026). Citation check: Internal conversion to the electronic ground state occurs via two distinct pathways for pyrimidine bases in aqueous solution. https://app.cochat.ai/papers/10.1073/pnas.0608055104
- The paper
- Hare, P. M., Crespo-Hernández, C. E., & Kohler, B. (2007). Internal conversion to the electronic ground state occurs via two distinct pathways for pyrimidine bases in aqueous solution. Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.0608055104
Data sources
Bibliographic data: Semantic Scholar, OpenAlex, Crossref.
Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
