Sunghwan Kim - Microhydration of cytosine and its radical anion: Cytosine·(H2O)n (n=1-5)

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      Publication Details (including relevant citation   information):

      S. Kim and H.F.   Schaefer;

      Journal of Chemical Physics,   2007126, 064301.



      Microhydration effects on cytosine and its radical anion have   been investigated theoretically, by explicitly considering   various structures of cytosine complexes with up to five water   molecules. Each successive water molecule (through n=5) is bound   by 7-10 kcal mol-1 to the relevant cytosine complex.   The hydration energies are uniformly higher for the analogous   anion systems. While the predicted vertical detachment energy   (VDE) of the isolated cytosine is only 0.48 eV, it is predicted   to increase to 1.27 eV for the lowest-lying pentahydrate of   cytosine. The adiabatic electron affinity (AEA) of cytosine was   also found to increase from 0.03 to 0.61 eV for the pentahydrate,   implying that the cytosine anion, while questionable in the gas   phase, is bound in aqueous solution. Both the VDE and AEA values   for cytosine are smaller than those of uracil and thymine for a   given hydration number. These results are in qualitative   agreement with available experimental results from   photodetachment-photoelectron spectroscopy studies of Schiedt   [Chem. Phys. 239, 511 (1998)].


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