Binding of gold clusters with DNA base pairs: A density functional study of neutral and anionic GC-[Au.sub.n] and AT-[Au.sub.n] (n = 4, 8) complexes

The density functional theory (DFT) is used to study the binding of clusters of gold atoms (Au) with the guanine-cytosine (GC) and adenine-thymine (AT) Watson-Crick DNA base pairs. The analysis has shown that guanine and adenine have high affinity for Au clusters and the calculated adiabatic electron affinities (AEAs) of the GC-[Au.sub.n] complexes (n = 4, 8) are found to be much larger than those of the isolated base pairs.