https://doi.org/10.1140/epjd/e2011-20273-2
Regular Article
Structural evolution study of 1−2 nm gold clusters
1
Instituto de Investigaciones en Materiales, Universidad Nacional
Autónoma de México, A.P. 70-360, C.P. 04510, Col. Copilco Universidad,
México D.F.,
México
2
Facultad de Ciencias, Universidad Nacional Autónoma de México,
A.P. 04510, Col. Copilco Universidad, México D.F., México
a e-mail: mbeltran@unam.mx
Received:
10
May
2011
Received in final form:
10
June
2011
Published online:
22
November
2011
We have explored lowest energy minima structures of gold atom clusters both, charged and
neutral (Au
with n = 20, 28, 34, 38, 55, 75, 101, 146, 147, 192, 212 atoms and
ν = 0, ±1). The structures have been obtained from
first principles generalized gradient approximation, density functional theory (DFT)
calculations based on norm-conserving pseudopotentials and numerical atomic basis sets. We
have found two new disordered or defective isomers lower in energy than their ordered
counterparts for n = 101, 147. The purpose of this work is to
systematically study the difference between the electronic properties of the two lowest
ordered and disordered isomers for each size. Our results agree with previous first
principle calculations and with some recent experimental results (Au20 and
Au101). For each case we report total energies, binding energies, ionization
potentials, electron affinities, density of states, highest occupied molecular
orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, Housdorff chirality measure
index and their simulated image in a high resolution transmission electron microscopy
(HRTEM). The calculated properties of the two low lying (ordered and disordered) isomers
show clear differences as to be singled out in a suitable experimental setting. An
extensive discussion on the evolution with size of the cohesive energy, the ionization
potentials, the electron affinities, the HOMO-LUMO gaps and their index of chirality to
determine the crossover between them is given.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2011