Relative stability of the La and Lb excited states in adenine and guanine: Direct evidence from TD-DFT calculations of MCD spectra
2014 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 5, no 11, 1806-1811 p.Article in journal (Refereed) Published
The relative position of La and Lb ππ* electronic states in purine nucleobases is a much debated topic, since it can strongly affect our understanding of their photoexcited dynamics. To assess this point, we calculated the absorption and magnetic circular dichroism (MCD) spectra of adenine, guanine, and their nucleosides in gas-phase and aqueous solution, exploiting recent developments in MCD computational technology within time-dependent density functional theory. MCD spectroscopy allows us to resolve the intense S0 La transition from the weak S 0Lb transition. The spectra obtained in water solution, by using B3LYP and CAM-B3LYP functionals and describing solvent effect by cluster models and by the polarizable continuum model (PCM), are in very good agreement with the experimental counterparts, thus providing direct and unambiguous evidence that the energy ordering predicted by TD-DFT, La < L b, is the correct one.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2014. Vol. 5, no 11, 1806-1811 p.
complex polarization propagator, DNA bases, hidden transitions, magnetic circular dichroism, photostability, solvent effect, Continuum mechanics, Density functional theory, Solvents, Spectroscopy, DNA basis, Magnetic circular dichroisms, Photo-stability, Solvent effects, Positive ions
IdentifiersURN: urn:nbn:se:kth:diva-198721DOI: 10.1021/jz500633tISI: 000337012500005PubMedID: 26273857ScopusID: 2-s2.0-84902075875OAI: oai:DiVA.org:kth-198721DiVA: diva2:1059115
QC 201612222016-12-222016-12-212016-12-22Bibliographically approved