Abstract :
Geometrical and electronic properties of Asn
(n = 2–15) neutrals, cations and anions have been investigated
using the density functional method of B3LYP.
Berny structural optimization and frequency analyses are
performed with the basis of 6-311 + G(d) for both neutrals
and charged ions. The total energies of these clusters are
then used to study the evolution of their binding energy,
relative stability, and electronic properties as a function of
size. The geometries are found to undergo a structural
change from two dimensional to three-dimensional when
the cluster contains four atoms. The geometrical changes
are companied by corresponding changes in the nearestneighbor
distances and coordination numbers. In the whole
size range, both ionization potential and electron affinity
have the tendency of decrease when the number of As units
in the cluster increases. The stability of clusters exhibits
strong even-odd alternations with several magic numbers.
The neutral Asn clusters are found to be even-numbered
with local maxima at n = 2 and 4, while the cationic and
anionic clusters are preferentially odd-numbered with As3
+,
As5
+, and As5 – being the most stable ions according to the
calculated results of the both energy gain and electronic
properties.
