35 research outputs found
Effect of hydrogen on ground state structures of small silicon clusters
We present results for ground state structures of small SiH (2 \leq
\emph{n} \leq 10) clusters using the Car-Parrinello molecular dynamics. In
particular, we focus on how the addition of a hydrogen atom affects the ground
state geometry, total energy and the first excited electronic level gap of an
Si cluster. We discuss the nature of bonding of hydrogen in these
clusters. We find that hydrogen bonds with two silicon atoms only in SiH,
SiH and SiH clusters, while in other clusters (i.e. SiH,
SiH, SiH, SiH, SiH and SiH) hydrogen is bonded
to only one silicon atom. Also in the case of a compact and closed silicon
cluster hydrogen bonds to the cluster from outside. We find that the first
excited electronic level gap of Si and SiH fluctuates as a function
of size and this may provide a first principles basis for the short-range
potential fluctuations in hydrogenated amorphous silicon. Our results show that
the addition of a single hydrogen can cause large changes in the electronic
structure of a silicon cluster, though the geometry is not much affected. Our
calculation of the lowest energy fragmentation products of SiH clusters
shows that hydrogen is easily removed from SiH clusters.Comment: one latex file named script.tex including table and figure caption.
Six postscript figure files. figure_1a.ps and figure_1b.ps are files
representing Fig. 1 in the main tex
A new method for the measurement of height and density profile of snow based on the attenuation of environmental gamma radioactivity
Theoretical wavelengths and transition rates for the iron ions Fe IX to Fe XIV in the soft X-ray region
The ileopsoas tunnel, a new antireflux technique for ureteroileal reimplantation: an experimental study in dogs
Psychosocial Care by General Practitioners—Where are the Problems? Results of a Demonstration Project on Quality Management in Psychosocial Primary Care
Energy Levels and Electric Dipole Transitions for Neutral Actinium (Z=89)
We have reported a relativistic multiconfiguration Dirac-Fock calculation including Breit and quantum electrodynamic contributions on the level structure of atomic actinium, Ac I (Z = 89). The computations have been carried out for the low 45 even and 60 odd-parity levels, and the electric dipole transition parameters (wavelengths, oscillator strengths and transition probabilities) for some transitions between these levels. Comparison has been also made with other results in available literature