1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
A molecular view of vapor deposited glasses
Rent:
Rent this article for
USD
10.1063/1.3586805
/content/aip/journal/jcp/134/19/10.1063/1.3586805
http://aip.metastore.ingenta.com/content/aip/journal/jcp/134/19/10.1063/1.3586805

Figures

Image of FIG. 1.
FIG. 1.

Specific heat of trehalose glasses at various temperatures. The thin dotted line corresponds to an “ordinary” glass prepared by slow cooling of the liquid at a rate of 0.001 K/ps and a pressure of 1 . Dark lines represent “stable” glasses prepared by vapor deposition with a substrate of 300, 330, 350, and 380 . The dark solid line represents the most “stable” glass prepared with a substrate temperature of 330 . The specific heat has been measured from the fluctuations of the energy measured during heating of the glass samples at a rate of 1 . Results reported have been averaged over 6 independent trajectories for each substrate temperature simulation performed with a box size of x = y = 12 nm and z = 18 nm.

Image of FIG. 2.
FIG. 2.

Normalized Debye-Waller factor 〈u 2(z)〉 for the “stable” glass as a function of the distance from the substrate layer. Different symbols represent different simulation time; 〈u 2〉 is represented on a logarithmic scale. Results are shown in increasing order of the number of growth cycles, as indicated by the arrow in the figure. The results correspond to the most “stable” glass prepared at a substrate temperature of 330 K, and have been averaged over 90 independent trajectories of different system size (as described in the Methods section).

Image of FIG. 3.
FIG. 3.

All-atom radial distribution function (rdf), g(r), for different systems. The solid curve represents the rdf of the crystal. The dashed and the dotted lines represent the rdf of the “stable” and the “ordinary” glass, respectively. The results shown have been taken from one of the trajectories of the most stable glass prepared at a substrate temperature of 330 K and a system size of x = y = z = 18 nm.

Image of FIG. 4.
FIG. 4.

Radial distribution function of the “stable” and the “ordinary” glasses measured in different directions. Plot (a) represents the rdf calculated by taking distances only in the xy directions, along the plane of the substrate. Plot (b) represents the rdf calculated by taking distances only in the z-direction, normal to the substrate. The solid curve represents the rdf for the “stable” glass, and the dotted curve corresponds to the “ordinary” glass. The results shown have been taken from one of the trajectories of the most stable glass prepared at a substrate temperature of 330 K and a system size of x = y = z = 18 nm.

Image of FIG. 5.
FIG. 5.

Layered structures of the vapor-deposited “stable” glass (taken from an arbitrarily chosen trajectory). Representative configuration of a vapor-deposited “stable” glass system. Different colors represent molecules deposited during different time intervals throughout the deposition process.

Image of FIG. 6.
FIG. 6.

(a) Local density profile of the center of mass of trehalose molecules as a function of the distance from the substrate layer. (b) Fourier transform of the local density profile for the “stable” glass. A large initial peak is consistent with the wide angle x-ray scattering (WAXS) pattern seen in experiments with “stable” glasses of IMC. (See Ref. 26) All results shown are from six independent runs of the vapor-deposited glass prepared at the substrate temperature of 330 K and a system size of x = y = z = 18 nm.

Tables

Generic image for table
Table I.

Difference in energy, density, and Q6 order parameters (See Refs. 66–68) for glasses prepared by different methods. A positive value for the difference in energy indicates that the energy is higher than that of the reference system. The energies are within ±0.14 of the corresponding values for the “ordinary” glass, while densities are within ±19 . Results reported have been averaged over 90 independent trajectories for the “stable” glasses prepared at the substrate temperatures of 330 K and over 36 independent trajectories for all other cases of “stable” glasses. The results for the “ordinary” glasses and the “crystal” structure have been averaged over 11 and 12 independent trajectories, respectively.

Loading

Article metrics loading...

/content/aip/journal/jcp/134/19/10.1063/1.3586805
2011-05-17
2014-04-18
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: A molecular view of vapor deposited glasses
http://aip.metastore.ingenta.com/content/aip/journal/jcp/134/19/10.1063/1.3586805
10.1063/1.3586805
SEARCH_EXPAND_ITEM