| 24 |
|
|
| 25 |
|
Much of the experimental work on this subject has been carried out in |
| 26 |
|
the Hartland and von~Plessen |
| 27 |
< |
groups.\cite{HartlandG.V._jp0276092,Hodak:2000rb,Hartland:2003yf,HuM._jp020581+,plech:195423} |
| 27 |
> |
groups.\cite{HartlandG.V._jp0276092,Hodak:2000rb,Hartland:2003yf,HuM._jp020581+,Petrova:2007qy,plech:195423} |
| 28 |
|
They have [BRIEF SURVEY OF THE EXPERIMENTAL WORK] |
| 29 |
|
|
| 30 |
|
|
| 32 |
|
surroundings, the large surface area to volume ratio makes the heat |
| 33 |
|
transfer to the surrounding solvent also a relatively rapid process. |
| 34 |
|
In our recent simulation study of the laser excitation of gold |
| 35 |
< |
nanoparticles,\cite{} we observed that the cooling rate for these |
| 35 |
> |
nanoparticles,\cite{VardemanC.F._jp051575r} we observed that the cooling rate for these |
| 36 |
|
particles (10$^{11}$-10$^{12}$ K/s) is in excess of the cooling rate |
| 37 |
|
required for glass formation in bulk metallic alloys. Given this |
| 38 |
|
fact, it may be possible to use laser excitation to melt, alloy and |
| 46 |
|
dynamics.\cite{Vardeman-II:2001jn} The Hume-Rothery rules suggest that |
| 47 |
|
alloys composed of Copper and Silver should be miscible in the solid |
| 48 |
|
state, because their lattice constants are within 15\% of each |
| 49 |
< |
another.\cite{XXX} Experimentally, however Ag-Cu alloys are a |
| 49 |
> |
another.\cite{kittel} Experimentally, however Ag-Cu alloys are a |
| 50 |
|
well-known exception to this rule and are only miscible in the liquid |
| 51 |
|
state given equilibrium conditions. Below the eutectic temperature of |
| 52 |
|
779 $^\circ$C and composition (60.1\% Ag, 39.9\% Cu), the |
| 54 |
|
$\alpha$ and $\beta$ phases, respectively. This behavior is due to a |
| 55 |
|
positive heat of mixing in both the solid and liquid phases. For the |
| 56 |
|
one-to-one composition fcc solid solution, $\Delta H$ is on the order |
| 57 |
< |
of +6~kJ/mole.\cite{Ma:2005zt} Non-equilibrium solid solutions may be |
| 57 |
> |
of +6~kJ/mole.\cite{Ma:2005fk} Non-equilibrium solid solutions may be |
| 58 |
|
formed by undercooling, and under these conditions, a |
| 59 |
|
compositionally-disordered $\gamma$ fcc phase can be formed. |
| 60 |
|
|
| 116 |
|
displacement that is linear in time (at long times). Glassy materials |
| 117 |
|
deviate significantly from this linear behavior at intermediate times, |
| 118 |
|
entering a sub-linear regime with a return to linear behavior in the |
| 119 |
< |
infinite time limit.\cite{Kob} However, diffusion in nanoparticles |
| 119 |
> |
infinite time limit.\cite{Kob:1999fk} However, diffusion in nanoparticles |
| 120 |
|
differs significantly from the bulk in that atoms are confined to a |
| 121 |
|
roughly spherical volume and cannot explore any region larger than the |
| 122 |
|
particle radius ($R$). In these confined geometries, $\langle r^2(t) |
| 123 |
< |
\rangle$ approaches a limiting value of $3R^2/40$.\cite{CHUCK} This limits the |
| 123 |
> |
\rangle$ approaches a limiting value of $3R^2/40$.\cite{ShibataT._ja026764r} This limits the |
| 124 |
|
utility of dynamical measures of glass formation when studying |
| 125 |
|
nanoparticles. |
| 126 |
|
|
| 133 |
|
et al.} defined an orientational bond order parameter that is |
| 134 |
|
sensitive to icosahedral ordering.\cite{Steinhardt:1983mo} This bond |
| 135 |
|
order parameter can therefore be used to characterize glass formation |
| 136 |
< |
in liquid and solid solutions.\cite{FrenkelXXX} |
| 136 |
> |
in liquid and solid solutions.\cite{wolde:9932} |
| 137 |
|
|
| 138 |
|
Theoretical molecular dynamics studies have been performed on the |
| 139 |
|
formation of amorphous single component nanoclusters of either |
