Indication of water droplet formation in hydrated clusters of cytosine and adenine: An electronic structure study using B3LYP, LMP2 and PM6

• Published in: Chemical physics letters Vol. 445; no. 4; pp. 303 - 308
• Main Authors: van Mourik, Tanja, Danilov, Victor I., Gonzalez, Eduardo, Deriabina, Alexandra, Poltev, Valery I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 13-09-2007
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2007.07.081

Hydrated cytosine and adenine structures with clustered water molecules (‘water droplets’) are energetically preferred over structures with waters distributed around the base.
The cytosine-(H
2O)
14 and adenine-(H
2O)
16 complexes were studied using B3LYP/6-31+G(d), LMP2/aug-cc-pV
nZ (
n
=
D,
T) and the new semiempirical method PM6. For each complex, two optimized structures were examined: one with water molecules distributed around the central base and one with a clustering of water molecules. The clustered structures were found to be energetically favored at all levels of theory employed (except at the B3LYP level with inclusion of zero-point energy correction, where the two cytosine-(H
2O)
14 structures are nearly iso-energetic).