Amorphous Dielectric Properties — Advanced Options Dialog Box

Advanced Options Dialog Box Features

• Initial density text box
• Relaxation protocol option menu
  • Save button
  • Final relaxation time text box
• Reset button

Initial density text box

Specify the initial density of the system to be built. The density and the number of molecules together define the initial cell size. The cell size changes in the equilibration process to relax into the equilibrium density. It is generally advisable to choose an initial density that is a bit lower than the experimental (or expected final) density, as starting with higher densities can cause failures in the building of the system or its equilibration.

Relaxation protocol option menu

Choose the relaxation protocol for the simulations. The settings for each protocol are listed below: if a setting is not mentioned, the default is used.

• Hofmann—use the Hofmann protocol. This is a robust protocol that works for most systems. This protocol includes three high-pressure stages to remove voids. The steps are listed below. The temperature schedules for annealing represent points (T,t) on a graph of temperature T vs simulation time t; the points are joined with straight lines, i.e. linear ramps in temperature.

  1. Brownian Dynamics, 100 ps, NVT, 10 K, 1 fs time step
  2. Molecular Dynamics, 300 ps, NVT, anneal with temperature schedule [[10 0] [300 50] [300 100] [600 150] [600 200] [300 250] [300 300]]
  3. Molecular Dynamics, 50 ps, NPT, 1000 bar
  4. Molecular Dynamics, 300 ps, NVT, anneal with temperature schedule [[300 0] [300 50] [600 100] [600 150] [300 200] [300 300]]
  5. Molecular Dynamics, 500 ps, NPT, 3000 bar, 300 K
  6. Molecular Dynamics, 250 ps, NVT, anneal with temperature schedule [[300 0] [600 50] [600 100] [300 150] [300 250]]
  7. Molecular Dynamics, 50 ps, NPT, 5000 bar, 300 K
  8. Molecular Dynamics, 150 ps, NVT, anneal with temperature schedule [[300 0] [600 50] [600 100] [300 150]]
  9. Molecular Dynamics, 100 ps, NVT, 300 K
  10. Molecular Dynamics, 10 ns, NPT, 1.01325 bar, 300 K

• Compressive—use the compressive protocol, in which a high-pressure stage is added towards the end to remove voids. This protocol is useful if the structures that are bulky and need more time to compress. The steps are listed below.

  1. Brownian Dynamics, 100 ps, NVT, 10 K, 1 fs time step
  2. Molecular Dynamics, 24 ps, NVT, 300 K, 1 fs time step
  3. Molecular Dynamics, 240 ps, NVT, 700 K, 1 fs time step
  4. Molecular Dynamics, 24 ps, NPT, 1.01325 bar, 300 K, 1 fs time step
  5. Molecular Dynamics, 240 ps, NPT, 1.01325 bar, 300 K
  6. Molecular Dynamics, 10 ns, NPT, 1013.25 bar, 300 K
  7. Molecular Dynamics, 10 ns, NPT, 1.01325 bar, 300 K

• Add New—Add a new relaxation protocol to the menu from an MSJ file. Opens a file selector, so you can find and select the protocol to add. The protocol is added to the menu for the duration of the Maestro session. You can save (make a copy) of the added protocols for use in future sessions with the Save button.

Save button

Save protocols added to the Relaxation protocol option menu for future use as protocols, in your User resources directory. The saved protocols are automatically added to the Relaxation protocol option menu.

Final relaxation time text box

Specify the length of the final relaxation stage, in ns. This is an added NPT stage with the specified length, run after the chosen relaxation protocol and just before the production simulation.

Reset button

Reset the panel to its default settings.