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Relaxation Dynamics of Hydrated Thymine, Thymidine, and Thymidine Monophosphate Probed by Liquid Jet Time-Resolved Photoelectron Spectroscopy.
Erickson, Blake A; Heim, Zachary N; Pieri, Elisa; Liu, Erica; Martinez, Todd J; Neumark, Daniel M.
Afiliação
  • Erickson BA; Department of Chemistry , University of California , Berkeley , California 94720 , United States.
  • Heim ZN; Department of Chemistry , University of California , Berkeley , California 94720 , United States.
  • Pieri E; Department of Chemistry , Stanford University , Stanford , California 94305 , United States.
  • Liu E; Department of Chemistry , University of California , Berkeley , California 94720 , United States.
  • Martinez TJ; Department of Chemistry , Stanford University , Stanford , California 94305 , United States.
  • Neumark DM; Department of Chemistry , University of California , Berkeley , California 94720 , United States.
J Phys Chem A ; 123(50): 10676-10684, 2019 Dec 19.
Article em En | MEDLINE | ID: mdl-31756106
ABSTRACT
The relaxation dynamics of thymine and its derivatives thymidine and thymidine monophosphate are studied using time-resolved photoelectron spectroscopy applied to a water microjet. Two absorption bands are studied; the first is a bright ππ* state which is populated using tunable-ultraviolet light in the range 4.74-5.17 eV and probed using a 6.20 eV probe pulse. By reversing the order of these pulses, a band containing multiple ππ* states is populated by the 6.20 eV pulse and the lower energy pulse serves as the probe. The lower lying ππ* state is found to decay in ∼400 fs in both thymine and thymidine independent of pump photon energy, while thymidine monophosphate decays vary from 670 to 840 fs with some pump energy dependence. The application of a computational quantum mechanical/molecular mechanical scheme at the XMS-CASPT2//CASSCF/AMBER level of theory suggests that conformational differences existing between thymidine and thymidine monophosphate in solution account for this difference. The higher lying ππ* band is found to decay in ∼600 fs in all three cases, but it is only able to be characterized when the 5.17 eV probe pulse is used. Notably, no long-lived signal from an nπ* state can be identified in either experiment on any of the three molecules.

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Ano de publicação: 2019 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Ano de publicação: 2019 Tipo de documento: Article